Feline Health / Genetics
Cat Disease and Genetic Variant Glossary
Evidence-reviewed explanations linked directly from the Cat Breed Disease Predispositions reference.
How to use this glossary
A breed association is not a diagnosis. “Congenital” does not automatically mean inherited. A DNA result applies to the exact variant tested and should not be generalized to every breed, lineage or clinically similar disorder.
Risk variants—particularly feline HCM markers—do not replace echocardiography. Pigmentation variants do not replace BAER hearing testing, and renal-cyst variants do not replace imaging.
Genetic-test interpretation
- Autosomal recessive
- One disease-associated copy usually indicates a carrier; two copies identify an at-risk genotype for the validated variant.
- Autosomal dominant
- One disease-associated copy may confer a phenotype or risk, but penetrance and severity can vary.
- X-linked recessive
- Hemizygous males are usually at greatest risk; heterozygous females are usually carriers but can vary.
- Susceptibility marker
- A positive result changes risk and is not equivalent to a clinical diagnosis.
- Negative result
- A negative result excludes only the tested variant; it does not exclude other variants or other causes of the same disease.
Alphabetical index
- Acrodermatitis enteropathica — SLC39A4-related
- Acute intermittent porphyria — HMBS-related
- Alpha-mannosidosis — MAN2B1-related
- ALX1-related craniofacial defect (Burmese head defect spectrum)
- Autoimmune lymphoproliferative syndrome — FASLG-related
- Brachycephalic conformation-associated disease
- Cerebellar hypoplasia
- Chediak-Higashi syndrome — LYST-related
- Cleft lip and/or palate
- Congenital heart defects
- Congenital myasthenic syndrome — COLQ-related
- Congenital portosystemic vascular anomaly
- Congenital sensorineural deafness associated with depigmentation
- Cystinuria — SLC7A9-related
- Diabetes mellitus — breed-associated risk
- Dystrophin-associated muscular dystrophy
- Ehlers-Danlos / cutaneous asthenia — COL5A1-related
- Factor XI deficiency — F11-related
- Familial AA amyloidosis
- FOXN1-related hypotrichosis with immune dysfunction
- GDF7-related holoprosencephaly
- Glycogen storage disease IV — GBE1-related
- GM1 gangliosidosis — GLB1-related
- GM2 gangliosidosis — HEXB-related
- HPS5-related pigmentation disorder ('pink-eye' phenotype)
- Hypertrophic cardiomyopathy (HCM)
- Hypokalemic polymyopathy — WNK4-related
- LTBP3-related skeletal dysplasia
- Maine Coon HCM — MYBPC3 A31P-associated risk
- Manx syndrome / spinal dysraphism
- Mucopolysaccharidosis VI — ARSB-related
- Munchkin chondrodysplasia — UGDH-related
- Myotonia congenita — CLCN1-related
- Myotubular myopathy — MTM1-related
- Niemann-Pick disease type C2 — NPC2-related
- PAX3-related dominant blue eyes / auditory-pigmentary syndrome
- Persian-family progressive retinal degeneration — AIPL1-related
- Polycystic kidney disease — PKD1-related
- Polycystic kidney disease — PKD2-related
- Polydactyly
- Primary congenital/early-onset glaucoma — LTBP2-related
- Progressive retinal atrophy — Bengal PRA-b (KIF3B-related)
- Progressive retinal atrophy — rdAc (CEP290-related)
- Progressive retinal atrophy — Rdy / CRX-related
- Pyruvate kinase deficiency — PKLR-related
- Ragdoll HCM — MYBPC3 R820W-associated risk
- Scottish Fold osteochondrodysplasia — TRPV4-related
- Spinal muscular atrophy — LIX1/LNPEP-region associated
- Thoracolumbar intervertebral disc disease
- TPO-related inherited hypothyroidism
Reviewed entries
Acrodermatitis enteropathica — SLC39A4-related
Evidence status: Established breed/line-associated inherited disorder with a cited molecular test
- What it is and how it can affect the cat
- Inherited zinc-transport disorder causing dermatologic and systemic disease.
- How it occurs or is acquired
- This is a germline, usually loss-of-function disorder; it is inherited rather than acquired. Clinical onset and severity remain disorder-specific.
- Inheritance and risk
- Autosomal recessive for the cited breed-associated form. A breed association does not mean every cat of that breed will develop the condition.
- What a positive genetic test means
- For the validated variant, one copy generally identifies a carrier and two copies identify an at-risk genotype. Confirm the exact variant and breed validation before clinical or breeding use.
Relevant breeds/varieties on this page: Turkish Van
Primary reference for this entry: Lyons LA. Genetic Testing: practical dos and don'ts for cats. J Feline Med Surg. 2024.
Acute intermittent porphyria — HMBS-related
Evidence status: Variant-specific inherited disorder; inheritance must be taken from the exact HMBS assay
- What it is and how it can affect the cat
- Inherited heme-biosynthesis disorder that can produce reddish-brown urine and variable neurologic or systemic signs.
- How it occurs or is acquired
- HMBS-associated disease is documented in Siamese/Oriental-related cats.
- Inheritance and risk
- Feline HMBS variants have not all been assigned the same inheritance model. Do not apply a general “dominant” or “recessive” label without confirming the exact tested variant. A breed association does not mean every cat of that breed will develop the condition.
- What a positive genetic test means
- A positive result establishes that the named HMBS variant was detected; zygosity, the assay’s validated inheritance model, penetrance, and compatible biochemical/clinical findings determine meaning.
Relevant breeds/varieties on this page: Oriental Longhair, Oriental Shorthair, Peterbald, Siamese
Primary reference for this entry: Lyons LA. Genetic Testing: practical dos and don'ts for cats. J Feline Med Surg. 2024.
Alpha-mannosidosis — MAN2B1-related
Evidence status: Established breed/line-associated inherited disorder with a cited molecular test
- What it is and how it can affect the cat
- Lysosomal storage disease causing neurologic and skeletal abnormalities.
- How it occurs or is acquired
- This is a germline, usually loss-of-function disorder; it is inherited rather than acquired. Clinical onset and severity remain disorder-specific.
- Inheritance and risk
- Autosomal recessive for the cited breed-associated form. A breed association does not mean every cat of that breed will develop the condition.
- What a positive genetic test means
- For the validated variant, one copy generally identifies a carrier and two copies identify an at-risk genotype. Confirm the exact variant and breed validation before clinical or breeding use.
Relevant breeds/varieties on this page: Exotic Shorthair, Himalayan, Persian, Scottish Fold, Scottish Fold Longhair, Selkirk Rex, Selkirk Rex Longhair
Primary reference for this entry: Lyons LA. Genetic Testing: practical dos and don'ts for cats. J Feline Med Surg. 2024.
ALX1-related craniofacial defect (Burmese head defect spectrum)
Evidence status: Established ALX1-associated developmental variant with genotype-dependent severity
- What it is and how it can affect the cat
- Severe craniofacial malformation described in Burmese-related populations; milder craniofacial effects may be present in heterozygous animals depending on the variant and genetic background.
- How it occurs or is acquired
- A causal ALX1-associated defect is established in affected lines. Current feline-genetics guidance groups several Burmese/Asian-derived breeds for monitoring.
- Inheritance and risk
- Autosomal incomplete-dominant/semidominant effect is reported in the Burmese head-defect spectrum: homozygotes can have severe craniofacial malformation, while heterozygotes may show a milder head-shape phenotype. A breed association does not mean every cat of that breed will develop the condition.
- What a positive genetic test means
- One copy identifies a heterozygote that may express a milder craniofacial phenotype; two copies identify the severe at-risk genotype. Interpretation is specific to the validated Burmese-line variant.
Relevant breeds/varieties on this page: American Shorthair, Australian Mist, Bombay, Burmese, Burmilla, Burmilla Longhair, Singapura
Primary reference for this entry: Lyons LA. Genetic Testing: practical dos and don'ts for cats. J Feline Med Surg. 2024.
Autoimmune lymphoproliferative syndrome — FASLG-related
Evidence status: Established breed/line-associated inherited disorder with a cited molecular test
- What it is and how it can affect the cat
- Inherited immune dysregulation characterized by abnormal lymphocyte survival and lymphoproliferation.
- How it occurs or is acquired
- This is a germline, usually loss-of-function disorder; it is inherited rather than acquired. Clinical onset and severity remain disorder-specific.
- Inheritance and risk
- Autosomal recessive for the cited breed-associated form. A breed association does not mean every cat of that breed will develop the condition.
- What a positive genetic test means
- For the validated variant, one copy generally identifies a carrier and two copies identify an at-risk genotype. Confirm the exact variant and breed validation before clinical or breeding use.
Relevant breeds/varieties on this page: British Longhair, British Shorthair
Primary reference for this entry: Lyons LA. Genetic Testing: practical dos and don'ts for cats. J Feline Med Surg. 2024.
Brachycephalic conformation-associated disease
Evidence status: Clinical, developmental, conformational or epidemiologic association—not a single diagnostic variant
- What it is and how it can affect the cat
- Shortened facial and skull conformation associated with respiratory obstruction, dental crowding/malocclusion, epiphora, ocular exposure, corneal disease and facial skin problems.
- How it occurs or is acquired
- The risk increases with the severity of brachycephaly; this is a selected conformational trait rather than a single validated disease variant.
- Inheritance and risk
- No single universally predictive inheritance model is established for this glossary entry. A breed association does not mean every cat of that breed will develop the condition.
- What a positive genetic test means
- No general positive-DNA-test meaning should be inferred. Use the disorder-appropriate clinical screening, imaging, laboratory testing or phenotypic examination.
Relevant breeds/varieties on this page: Exotic Shorthair, Himalayan, Persian
Primary reference for this entry: UFAW — Persian brachycephaly and associated health problems.
Cerebellar hypoplasia
Evidence status: Clinical, developmental, conformational or epidemiologic association—not a single diagnostic variant
- What it is and how it can affect the cat
- Underdevelopment of the cerebellum causing lifelong nonprogressive ataxia, intention tremor and hypermetria.
- How it occurs or is acquired
- Congenital but usually not a breed-specific inherited disease; prenatal viral injury, especially feline panleukopenia exposure, is an important cause.
- Inheritance and risk
- No single universally predictive inheritance model is established for this glossary entry. A breed association does not mean every cat of that breed will develop the condition.
- What a positive genetic test means
- No general positive-DNA-test meaning should be inferred. Use the disorder-appropriate clinical screening, imaging, laboratory testing or phenotypic examination.
Relevant breeds/varieties on this page: No specific TICA breed association is asserted on this page.
Primary reference for this entry: Merck Veterinary Manual — Congenital and inherited disorders of the nervous system in cats.
Chediak-Higashi syndrome — LYST-related
Evidence status: Established breed/line-associated inherited disorder with a cited molecular test
- What it is and how it can affect the cat
- Rare inherited disorder affecting lysosomal trafficking, pigmentation and hemostasis.
- How it occurs or is acquired
- This is a germline, usually loss-of-function disorder; it is inherited rather than acquired. Clinical onset and severity remain disorder-specific.
- Inheritance and risk
- Autosomal recessive for the cited breed-associated form. A breed association does not mean every cat of that breed will develop the condition.
- What a positive genetic test means
- For the validated variant, one copy generally identifies a carrier and two copies identify an at-risk genotype. Confirm the exact variant and breed validation before clinical or breeding use.
Relevant breeds/varieties on this page: Exotic Shorthair, Himalayan, Persian, Scottish Fold, Scottish Fold Longhair, Selkirk Rex, Selkirk Rex Longhair
Primary reference for this entry: Lyons LA. Genetic Testing: practical dos and don'ts for cats. J Feline Med Surg. 2024.
Cleft lip and/or palate
Evidence status: Clinical, developmental, conformational or epidemiologic association—not a single diagnostic variant
- What it is and how it can affect the cat
- Failure of normal embryonic fusion of facial or palatal structures, producing an oral-nasal communication.
- How it occurs or is acquired
- Congenital; may be genetic, environmental or multifactorial. Merck notes that cleft palate is uncommon in cats but occurs more often in Siamese.
- Inheritance and risk
- No single universally predictive inheritance model is established for this glossary entry. A breed association does not mean every cat of that breed will develop the condition.
- What a positive genetic test means
- No general positive-DNA-test meaning should be inferred. Use the disorder-appropriate clinical screening, imaging, laboratory testing or phenotypic examination.
Relevant breeds/varieties on this page: Siamese
Primary reference for this entry: Merck Veterinary Manual — Congenital and inherited disorders of the digestive system in cats.
Congenital heart defects
Evidence status: Clinical, developmental, conformational or epidemiologic association—not a single diagnostic variant
- What it is and how it can affect the cat
- Includes ventricular/atrial septal defects, atrioventricular valve dysplasia, patent ductus arteriosus, aortic stenosis, tetralogy of Fallot and other structural defects present at birth.
- How it occurs or is acquired
- Congenital heart disease is uncommon in cats overall; inherited risk is established or suspected for some defects, but breed-specific causation is often not defined.
- Inheritance and risk
- No single universally predictive inheritance model is established for this glossary entry. A breed association does not mean every cat of that breed will develop the condition.
- What a positive genetic test means
- No general positive-DNA-test meaning should be inferred. Use the disorder-appropriate clinical screening, imaging, laboratory testing or phenotypic examination.
Relevant breeds/varieties on this page: No specific TICA breed association is asserted on this page.
Primary reference for this entry: Merck Veterinary Manual — Congenital and inherited disorders of the cardiovascular system of cats.
Congenital myasthenic syndrome — COLQ-related
Evidence status: Established breed/line-associated inherited disorder with a cited molecular test
- What it is and how it can affect the cat
- Inherited neuromuscular-junction disorder causing weakness, fatigability and characteristic abnormal gait or posture.
- How it occurs or is acquired
- This is a germline, usually loss-of-function disorder; it is inherited rather than acquired. Clinical onset and severity remain disorder-specific.
- Inheritance and risk
- Autosomal recessive for the cited breed-associated form. A breed association does not mean every cat of that breed will develop the condition.
- What a positive genetic test means
- For the validated variant, one copy generally identifies a carrier and two copies identify an at-risk genotype. Confirm the exact variant and breed validation before clinical or breeding use.
Relevant breeds/varieties on this page: Devon Rex, Selkirk Rex, Selkirk Rex Longhair, Sphynx
Primary reference for this entry: Governing Council of the Cat Fancy — Gene testing.
Congenital portosystemic vascular anomaly
Evidence status: Clinical, developmental, conformational or epidemiologic association—not a single diagnostic variant
- What it is and how it can affect the cat
- An abnormal vessel permits portal blood to bypass the liver, causing poor growth, gastrointestinal signs, urinary abnormalities and hepatic encephalopathy.
- How it occurs or is acquired
- Congenital shunts occur in cats; Merck notes increased prevalence in Persian and Himalayan cats.
- Inheritance and risk
- No single universally predictive inheritance model is established for this glossary entry. A breed association does not mean every cat of that breed will develop the condition.
- What a positive genetic test means
- No general positive-DNA-test meaning should be inferred. Use the disorder-appropriate clinical screening, imaging, laboratory testing or phenotypic examination.
Relevant breeds/varieties on this page: Himalayan, Persian
Primary reference for this entry: Merck Veterinary Manual — Hepatic portal venous hypoperfusion / congenital portosystemic vascular anomalies.
Congenital sensorineural deafness associated with depigmentation
Evidence status: Clinical, developmental, conformational or epidemiologic association—not a single diagnostic variant
- What it is and how it can affect the cat
- Congenital unilateral or bilateral deafness associated particularly with dominant white/blue-eyed pigmentation phenotypes.
- How it occurs or is acquired
- Pigmentation-associated deafness has a genetic/developmental basis, but risk depends on the specific white/blue-eye allele and genetic background.
- Inheritance and risk
- No single universally predictive inheritance model is established for this glossary entry. A breed association does not mean every cat of that breed will develop the condition.
- What a positive genetic test means
- No general positive-DNA-test meaning should be inferred. Use the disorder-appropriate clinical screening, imaging, laboratory testing or phenotypic examination.
Relevant breeds/varieties on this page: Khaomanee, Turkish Angora
Primary reference for this entry: Merck Veterinary Manual — Commonly reported congenital and inherited defects in cats.
Cystinuria — SLC7A9-related
Evidence status: Established SLC7A9-associated disease, but variant and inheritance are heterogeneous
- What it is and how it can affect the cat
- Inherited renal amino-acid transport defect that can predispose to cystine crystalluria and urolith formation.
- How it occurs or is acquired
- Pathogenic SLC7A9 variants are documented in cats and are included in breed-monitoring guidance for several breeds.
- Inheritance and risk
- Feline cystinuria is genetically heterogeneous. SLC7A9-associated forms can differ in dominance, recessivity and penetrance; the gene name alone does not define inheritance. A breed association does not mean every cat of that breed will develop the condition.
- What a positive genetic test means
- Interpret the exact SLC7A9 variant and zygosity using the laboratory’s validated model. A positive genotype indicates altered cystine-transport risk, not that obstructive cystine stones are currently present.
Relevant breeds/varieties on this page: Devon Rex, Maine Coon, Maine Coon Polydactyl, Oriental Longhair, Oriental Shorthair, Peterbald, Selkirk Rex, Selkirk Rex Longhair, Siamese, Sphynx
Primary reference for this entry: Lyons LA. Genetic Testing: practical dos and don'ts for cats. J Feline Med Surg. 2024.
Diabetes mellitus — breed-associated risk
Evidence status: Clinical, developmental, conformational or epidemiologic association—not a single diagnostic variant
- What it is and how it can affect the cat
- Persistent hyperglycemia caused by inadequate insulin action and/or secretion.
- How it occurs or is acquired
- Epidemiologic studies have reported increased risk in Burmese, Norwegian Forest and Tonkinese cats; obesity, age, sex and environment remain important modifiers.
- Inheritance and risk
- No single universally predictive inheritance model is established for this glossary entry. A breed association does not mean every cat of that breed will develop the condition.
- What a positive genetic test means
- No general positive-DNA-test meaning should be inferred. Use the disorder-appropriate clinical screening, imaging, laboratory testing or phenotypic examination.
Relevant breeds/varieties on this page: Burmese, Norwegian Forest, Tonkinese
Primary reference for this entry: O'Neill et al. Epidemiology of diabetes mellitus in cats attending primary-care practices in England.
Dystrophin-associated muscular dystrophy
Evidence status: Established X-linked inherited disorder with a cited molecular association
- What it is and how it can affect the cat
- X-linked muscular dystrophy causing progressive muscle weakness and muscle enlargement/degeneration.
- How it occurs or is acquired
- This is a germline X-chromosome disorder inherited rather than acquired.
- Inheritance and risk
- X-linked recessive for the cited form; hemizygous males are at greatest risk, while heterozygous females are usually carriers but can vary. A breed association does not mean every cat of that breed will develop the condition.
- What a positive genetic test means
- A positive result must be interpreted by sex and zygosity. A male with the disease-associated allele is at risk; a heterozygous female is generally a carrier. Correlate with clinical findings.
Relevant breeds/varieties on this page: Maine Coon, Maine Coon Polydactyl
Primary reference for this entry: Lyons LA. Genetic Testing: practical dos and don'ts for cats. J Feline Med Surg. 2024.
Ehlers-Danlos / cutaneous asthenia — COL5A1-related
Evidence status: COL5A1-associated connective-tissue disease; variant and lineage validation required
- What it is and how it can affect the cat
- Connective-tissue disorder that can produce abnormally fragile, hyperextensible skin and impaired wound integrity.
- How it occurs or is acquired
- Pathogenic COL5A1 variants have been documented in cats, including breed-associated forms.
- Inheritance and risk
- Validated COL5A1-associated classical Ehlers-Danlos forms are generally autosomal dominant, but feline cutaneous asthenia is genetically heterogeneous. A breed association does not mean every cat of that breed will develop the condition.
- What a positive genetic test means
- A positive result is meaningful only for the exact COL5A1 variant and lineage validated by the laboratory. It should be correlated with skin fragility, hyperextensibility, scarring and family history.
Relevant breeds/varieties on this page: Australian Mist, Bengal, Bengal Longhair, Bombay, Burmese, Burmilla, Burmilla Longhair, Singapura
Primary reference for this entry: Lyons LA. Genetic Testing: practical dos and don'ts for cats. J Feline Med Surg. 2024.
Factor XI deficiency — F11-related
Evidence status: Established breed/line-associated inherited disorder with a cited molecular test
- What it is and how it can affect the cat
- Inherited coagulation abnormality that may be clinically silent until surgery, trauma or another hemostatic challenge.
- How it occurs or is acquired
- This is a germline, usually loss-of-function disorder; it is inherited rather than acquired. Clinical onset and severity remain disorder-specific.
- Inheritance and risk
- Autosomal recessive for the cited breed-associated form. A breed association does not mean every cat of that breed will develop the condition.
- What a positive genetic test means
- For the validated variant, one copy generally identifies a carrier and two copies identify an at-risk genotype. Confirm the exact variant and breed validation before clinical or breeding use.
Relevant breeds/varieties on this page: Maine Coon, Maine Coon Polydactyl
Primary reference for this entry: Lyons LA. Genetic Testing: practical dos and don'ts for cats. J Feline Med Surg. 2024.
Familial AA amyloidosis
Evidence status: Clinical, developmental, conformational or epidemiologic association—not a single diagnostic variant
- What it is and how it can affect the cat
- Systemic AA amyloid deposition. In Abyssinian/Somali cats renal disease is prominent; in Siamese/Oriental lines hepatic deposition and liver rupture are important clinical concerns.
- How it occurs or is acquired
- Familial/breed-associated disease is well recognized, but the full causal architecture is not defined as a single universally predictive DNA test.
- Inheritance and risk
- No single universally predictive inheritance model is established for this glossary entry. A breed association does not mean every cat of that breed will develop the condition.
- What a positive genetic test means
- No general positive-DNA-test meaning should be inferred. Use the disorder-appropriate clinical screening, imaging, laboratory testing or phenotypic examination.
Relevant breeds/varieties on this page: Abyssinian, Oriental Longhair, Oriental Shorthair, Siamese, Somali
Primary reference for this entry: Single nucleotide polymorphisms associated with AA-amyloidosis in Siamese and Oriental Shorthair cats.
FOXN1-related hypotrichosis with immune dysfunction
Evidence status: Established breed/line-associated inherited disorder with a cited molecular test
- What it is and how it can affect the cat
- Congenital hair deficiency associated with impaired thymic/immune development and reduced survival.
- How it occurs or is acquired
- This is a germline, usually loss-of-function disorder; it is inherited rather than acquired. Clinical onset and severity remain disorder-specific.
- Inheritance and risk
- Autosomal recessive for the cited breed-associated form. A breed association does not mean every cat of that breed will develop the condition.
- What a positive genetic test means
- For the validated variant, one copy generally identifies a carrier and two copies identify an at-risk genotype. Confirm the exact variant and breed validation before clinical or breeding use.
Relevant breeds/varieties on this page: Birman
Primary reference for this entry: Lyons LA. Genetic Testing: practical dos and don'ts for cats. J Feline Med Surg. 2024.
GDF7-related holoprosencephaly
Evidence status: Published Toyger-line GDF7 association; general predictive testing remains limited
- What it is and how it can affect the cat
- Severe developmental forebrain and craniofacial malformation.
- How it occurs or is acquired
- A breed-associated GDF7 variant is documented in Toyger cats.
- Inheritance and risk
- A heritable GDF7 deletion has been reported in an affected Toyger family, but the evidence does not justify extending a simple inheritance or penetrance estimate to all Toygers. A breed association does not mean every cat of that breed will develop the condition.
- What a positive genetic test means
- Detection may support risk in the validated family line. A negative result cannot exclude other genetic or developmental causes of forebrain malformation.
Relevant breeds/varieties on this page: Toyger
Primary reference for this entry: Lyons LA. Genetic Testing: practical dos and don'ts for cats. J Feline Med Surg. 2024.
Glycogen storage disease IV — GBE1-related
Evidence status: Established breed/line-associated inherited disorder with a cited molecular test
- What it is and how it can affect the cat
- Inherited glycogen branching-enzyme deficiency that can cause fetal loss, neonatal death or progressive neuromuscular disease.
- How it occurs or is acquired
- This is a germline, usually loss-of-function disorder; it is inherited rather than acquired. Clinical onset and severity remain disorder-specific.
- Inheritance and risk
- Autosomal recessive for the cited breed-associated form. A breed association does not mean every cat of that breed will develop the condition.
- What a positive genetic test means
- For the validated variant, one copy generally identifies a carrier and two copies identify an at-risk genotype. Confirm the exact variant and breed validation before clinical or breeding use.
Relevant breeds/varieties on this page: Norwegian Forest
Primary reference for this entry: Lyons LA. Genetic Testing: practical dos and don'ts for cats. J Feline Med Surg. 2024.
GM1 gangliosidosis — GLB1-related
Evidence status: Established breed/line-associated inherited disorder with a cited molecular test
- What it is and how it can affect the cat
- Lysosomal storage disorder causing progressive neurologic disease.
- How it occurs or is acquired
- This is a germline, usually loss-of-function disorder; it is inherited rather than acquired. Clinical onset and severity remain disorder-specific.
- Inheritance and risk
- Autosomal recessive for the cited breed-associated form. A breed association does not mean every cat of that breed will develop the condition.
- What a positive genetic test means
- For the validated variant, one copy generally identifies a carrier and two copies identify an at-risk genotype. Confirm the exact variant and breed validation before clinical or breeding use.
Relevant breeds/varieties on this page: Korat, Oriental Longhair, Oriental Shorthair, Peterbald, Siamese
Primary reference for this entry: Lyons LA. Genetic Testing: practical dos and don'ts for cats. J Feline Med Surg. 2024.
GM2 gangliosidosis — HEXB-related
Evidence status: Established breed/line-associated inherited disorder with a cited molecular test
- What it is and how it can affect the cat
- Lysosomal storage disease causing progressive neurologic dysfunction.
- How it occurs or is acquired
- This is a germline, usually loss-of-function disorder; it is inherited rather than acquired. Clinical onset and severity remain disorder-specific.
- Inheritance and risk
- Autosomal recessive for the cited breed-associated form. A breed association does not mean every cat of that breed will develop the condition.
- What a positive genetic test means
- For the validated variant, one copy generally identifies a carrier and two copies identify an at-risk genotype. Confirm the exact variant and breed validation before clinical or breeding use.
Relevant breeds/varieties on this page: Australian Mist, Bombay, Burmese, Burmilla, Burmilla Longhair, Korat, Singapura
Primary reference for this entry: Lyons LA. Genetic Testing: practical dos and don'ts for cats. J Feline Med Surg. 2024.
HPS5-related pigmentation disorder ('pink-eye' phenotype)
Evidence status: Established breed/line-associated inherited disorder with a cited molecular test
- What it is and how it can affect the cat
- Inherited pigmentation abnormality reported in Donskoy cats.
- How it occurs or is acquired
- This is a germline, usually loss-of-function disorder; it is inherited rather than acquired. Clinical onset and severity remain disorder-specific.
- Inheritance and risk
- Autosomal recessive for the cited breed-associated form. A breed association does not mean every cat of that breed will develop the condition.
- What a positive genetic test means
- For the validated variant, one copy generally identifies a carrier and two copies identify an at-risk genotype. Confirm the exact variant and breed validation before clinical or breeding use.
Relevant breeds/varieties on this page: Donskoy
Primary reference for this entry: Lyons LA. Genetic Testing: practical dos and don'ts for cats. J Feline Med Surg. 2024.
Hypertrophic cardiomyopathy (HCM)
Evidence status: Clinical, developmental, conformational or epidemiologic association—not a single diagnostic variant
- What it is and how it can affect the cat
- Primary myocardial disease characterized by left-ventricular hypertrophy not explained by another systemic cause. Cats may remain subclinical or develop heart failure, arterial thromboembolism, arrhythmia or sudden death.
- How it occurs or is acquired
- Pedigree-breed risk is supported for several breeds. A negative breed-specific DNA test does not exclude HCM because HCM is genetically heterogeneous.
- Inheritance and risk
- No single universally predictive inheritance model is established for this glossary entry. A breed association does not mean every cat of that breed will develop the condition.
- What a positive genetic test means
- No general positive-DNA-test meaning should be inferred. Use the disorder-appropriate clinical screening, imaging, laboratory testing or phenotypic examination.
Relevant breeds/varieties on this page: American Shorthair, Bengal, Bengal Longhair, Birman, British Shorthair, Chartreux, Cornish Rex, Himalayan, Maine Coon, Maine Coon Polydactyl, Norwegian Forest, Persian, Ragdoll, Scottish Fold, Scottish Fold Longhair, Siberian, Sphynx
Primary reference for this entry: ACVIM consensus statement on classification, diagnosis and management of cardiomyopathies in cats.
Hypokalemic polymyopathy — WNK4-related
Evidence status: Established breed/line-associated inherited disorder with a cited molecular test
- What it is and how it can affect the cat
- Inherited renal potassium-wasting disorder that can cause episodic or persistent muscle weakness, ventroflexion of the neck and gait abnormalities.
- How it occurs or is acquired
- This is a germline, usually loss-of-function disorder; it is inherited rather than acquired. Clinical onset and severity remain disorder-specific.
- Inheritance and risk
- Autosomal recessive for the cited breed-associated form. A breed association does not mean every cat of that breed will develop the condition.
- What a positive genetic test means
- For the validated variant, one copy generally identifies a carrier and two copies identify an at-risk genotype. Confirm the exact variant and breed validation before clinical or breeding use.
Relevant breeds/varieties on this page: Australian Mist, Bombay, Burmese, Burmilla, Burmilla Longhair, Singapura
Primary reference for this entry: Governing Council of the Cat Fancy — Gene testing.
LTBP3-related skeletal dysplasia
Evidence status: Established breed/line-associated inherited disorder with a cited molecular test
- What it is and how it can affect the cat
- Inherited skeletal-development disorder associated with disproportionate growth abnormalities.
- How it occurs or is acquired
- This is a germline, usually loss-of-function disorder; it is inherited rather than acquired. Clinical onset and severity remain disorder-specific.
- Inheritance and risk
- Autosomal recessive for the cited breed-associated form. A breed association does not mean every cat of that breed will develop the condition.
- What a positive genetic test means
- For the validated variant, one copy generally identifies a carrier and two copies identify an at-risk genotype. Confirm the exact variant and breed validation before clinical or breeding use.
Relevant breeds/varieties on this page: British Longhair, British Shorthair
Primary reference for this entry: Lyons LA. Genetic Testing: practical dos and don'ts for cats. J Feline Med Surg. 2024.
Maine Coon HCM — MYBPC3 A31P-associated risk
Evidence status: Validated Maine Coon MYBPC3 A31P susceptibility variant; not diagnostic for HCM
- What it is and how it can affect the cat
- Breed-associated hypertrophic cardiomyopathy risk variant in MYBPC3.
- How it occurs or is acquired
- The A31P variant increases HCM risk but has incomplete penetrance; DNA status does not replace echocardiographic screening.
- Inheritance and risk
- Autosomal dominant susceptibility with incomplete, age-dependent penetrance. Homozygous cats generally have greater risk than heterozygotes, but genotype does not determine an individual outcome. A breed association does not mean every cat of that breed will develop the condition.
- What a positive genetic test means
- A positive A31P result increases HCM risk in Maine Coons but does not diagnose hypertrophy. A negative result does not exclude HCM; echocardiographic screening remains necessary.
Relevant breeds/varieties on this page: Maine Coon, Maine Coon Polydactyl
Primary reference for this entry: UC Davis VGL — Hypertrophic Cardiomyopathy in Maine Coons.
Manx syndrome / spinal dysraphism
Evidence status: Established dominant tailless phenotype with variable spinal-dysraphism risk
- What it is and how it can affect the cat
- Spectrum of sacrocaudal vertebral and spinal-cord abnormalities associated with the tailless Manx phenotype; severe cases may cause paresis and urinary/fecal incontinence.
- How it occurs or is acquired
- The tailless phenotype is inherited as a dominant trait with embryonic lethality in homozygotes; clinical severity among surviving heterozygotes is variable.
- Inheritance and risk
- Autosomal dominant with variable expression; homozygosity is generally considered embryonic lethal. Surviving heterozygotes vary from clinically normal tailless cats to severe spinal disease. A breed association does not mean every cat of that breed will develop the condition.
- What a positive genetic test means
- Genotype or tailless phenotype cannot predict neurologic severity. Clinical neurologic, orthopedic and urinary/fecal assessment is required.
Relevant breeds/varieties on this page: Cymric, Manx
Primary reference for this entry: UFAW — Manx syndrome.
Mucopolysaccharidosis VI — ARSB-related
Evidence status: Established breed/line-associated inherited disorder with a cited molecular test
- What it is and how it can affect the cat
- Inherited lysosomal storage disease causing skeletal, ocular and systemic abnormalities; severity depends on the causal variant.
- How it occurs or is acquired
- This is a germline, usually loss-of-function disorder; it is inherited rather than acquired. Clinical onset and severity remain disorder-specific.
- Inheritance and risk
- Autosomal recessive for the cited breed-associated form. A breed association does not mean every cat of that breed will develop the condition.
- What a positive genetic test means
- For the validated variant, one copy generally identifies a carrier and two copies identify an at-risk genotype. Confirm the exact variant and breed validation before clinical or breeding use.
Relevant breeds/varieties on this page: Oriental Longhair, Oriental Shorthair, Peterbald, Siamese
Primary reference for this entry: Lyons LA. Genetic Testing: practical dos and don'ts for cats. J Feline Med Surg. 2024.
Munchkin chondrodysplasia — UGDH-related
Evidence status: Established UGDH-associated dominant short-limb phenotype with welfare implications
- What it is and how it can affect the cat
- Disproportionate dwarfism with shortened limbs and characteristic long-bone changes.
- How it occurs or is acquired
- A UGDH structural variant is associated with the short-legged Munchkin phenotype; inheritance is dominant with evidence consistent with homozygous lethality.
- Inheritance and risk
- Autosomal dominant for disproportionate short limbs, with evidence consistent with homozygous lethality. Clinical skeletal effects can vary among surviving heterozygotes. A breed association does not mean every cat of that breed will develop the condition.
- What a positive genetic test means
- One copy predicts the short-legged phenotype and associated skeletal-risk genotype; it does not quantify pain or mobility impairment. Two-copy conceptions may not survive.
Relevant breeds/varieties on this page: Minuet, Minuet Longhair, Munchkin, Munchkin Longhair
Primary reference for this entry: OMIA — UGDH-related chondrodysplasia in Munchkin cats.
Myotonia congenita — CLCN1-related
Evidence status: Established breed/line-associated inherited disorder with a cited molecular test
- What it is and how it can affect the cat
- Inherited skeletal-muscle channelopathy causing stiffness and delayed muscle relaxation.
- How it occurs or is acquired
- This is a germline, usually loss-of-function disorder; it is inherited rather than acquired. Clinical onset and severity remain disorder-specific.
- Inheritance and risk
- Autosomal recessive for the cited breed-associated form. A breed association does not mean every cat of that breed will develop the condition.
- What a positive genetic test means
- For the validated variant, one copy generally identifies a carrier and two copies identify an at-risk genotype. Confirm the exact variant and breed validation before clinical or breeding use.
Relevant breeds/varieties on this page: Australian Mist, Bombay, Burmese, Burmilla, Burmilla Longhair, Singapura
Primary reference for this entry: Lyons LA. Genetic Testing: practical dos and don'ts for cats. J Feline Med Surg. 2024.
Myotubular myopathy — MTM1-related
Evidence status: Established X-linked inherited disorder with a cited molecular association
- What it is and how it can affect the cat
- X-linked inherited myopathy causing severe muscle weakness.
- How it occurs or is acquired
- This is a germline X-chromosome disorder inherited rather than acquired.
- Inheritance and risk
- X-linked recessive for the cited form; hemizygous males are at greatest risk, while heterozygous females are usually carriers but can vary. A breed association does not mean every cat of that breed will develop the condition.
- What a positive genetic test means
- A positive result must be interpreted by sex and zygosity. A male with the disease-associated allele is at risk; a heterozygous female is generally a carrier. Correlate with clinical findings.
Relevant breeds/varieties on this page: Maine Coon, Maine Coon Polydactyl
Primary reference for this entry: Lyons LA. Genetic Testing: practical dos and don'ts for cats. J Feline Med Surg. 2024.
Niemann-Pick disease type C2 — NPC2-related
Evidence status: Established breed/line-associated inherited disorder with a cited molecular test
- What it is and how it can affect the cat
- Lysosomal lipid-storage disorder causing progressive neurologic disease.
- How it occurs or is acquired
- This is a germline, usually loss-of-function disorder; it is inherited rather than acquired. Clinical onset and severity remain disorder-specific.
- Inheritance and risk
- Autosomal recessive for the cited breed-associated form. A breed association does not mean every cat of that breed will develop the condition.
- What a positive genetic test means
- For the validated variant, one copy generally identifies a carrier and two copies identify an at-risk genotype. Confirm the exact variant and breed validation before clinical or breeding use.
Relevant breeds/varieties on this page: Oriental Longhair, Oriental Shorthair, Peterbald, Siamese
Primary reference for this entry: Lyons LA. Genetic Testing: practical dos and don'ts for cats. J Feline Med Surg. 2024.
PAX3-related dominant blue eyes / auditory-pigmentary syndrome
Evidence status: PAX3-associated dominant pigmentation trait; auditory risk is allele and lineage dependent
- What it is and how it can affect the cat
- Lineage-associated pigmentation phenotype that can be accompanied by unilateral or bilateral sensorineural deafness.
- How it occurs or is acquired
- Multiple PAX3 variants have been reported in domestic cats, including Maine Coon lines; risk depends on the specific variant and lineage.
- Inheritance and risk
- Autosomal dominant for validated dominant-blue-eye alleles. Deafness penetrance varies with the specific PAX3 variant and lineage. A breed association does not mean every cat of that breed will develop the condition.
- What a positive genetic test means
- A positive result predicts the relevant pigmentation allele, not hearing status. BAER testing is required to determine unilateral or bilateral deafness.
Relevant breeds/varieties on this page: Maine Coon, Maine Coon Polydactyl
Primary reference for this entry: OMIA — PAX3-related auditory-pigmentary syndrome / dominant blue eyes in cats.
Persian-family progressive retinal degeneration — AIPL1-related
Evidence status: Established breed/line-associated inherited disorder with a cited molecular test
- What it is and how it can affect the cat
- Early-onset inherited retinal degeneration described in Persian-family cats.
- How it occurs or is acquired
- This is a germline, usually loss-of-function disorder; it is inherited rather than acquired. Clinical onset and severity remain disorder-specific.
- Inheritance and risk
- Autosomal recessive for the cited breed-associated form. A breed association does not mean every cat of that breed will develop the condition.
- What a positive genetic test means
- For the validated variant, one copy generally identifies a carrier and two copies identify an at-risk genotype. Confirm the exact variant and breed validation before clinical or breeding use.
Relevant breeds/varieties on this page: Exotic Shorthair, Himalayan, Persian, Scottish Fold, Scottish Fold Longhair, Selkirk Rex, Selkirk Rex Longhair
Primary reference for this entry: Lyons LA. Genetic Testing: practical dos and don'ts for cats. J Feline Med Surg. 2024.
Polycystic kidney disease — PKD1-related
Evidence status: Established breed/line-associated inherited disorder with a cited molecular test
- What it is and how it can affect the cat
- Progressive bilateral renal cyst formation that can lead to chronic kidney disease.
- How it occurs or is acquired
- This is a germline disorder inherited rather than acquired. Age at clinical expression and penetrance may vary.
- Inheritance and risk
- Autosomal dominant for the cited breed-associated form. A breed association does not mean every cat of that breed will develop the condition.
- What a positive genetic test means
- One validated disease-associated copy can confer risk. A positive result should be interpreted with penetrance, age, phenotype and the exact breed/line in which the assay was validated.
Relevant breeds/varieties on this page: American Shorthair, British Longhair, British Shorthair, Exotic Shorthair, Himalayan, Minuet, Minuet Longhair, Minuet Talls, Minuet Talls Longhair, Persian, Ragdoll, Scottish Fold, Scottish Fold Longhair, Scottish Straight, Scottish Straight Longhair, Selkirk Rex, Selkirk Rex Longhair
Primary reference for this entry: UC Davis VGL — Polycystic Kidney Disease (PKD1).
Polycystic kidney disease — PKD2-related
Evidence status: Likely dominant private PKD2 variant; limited population validity
- What it is and how it can affect the cat
- Inherited cystic kidney disease described in Siberian cats.
- How it occurs or is acquired
- A breed-associated PKD2 variant is listed in current feline-genetics guidance; interpretation should remain tied to the validated breed/line.
- Inheritance and risk
- The reported Siberian/Neva Masquerade PKD2 deletion segregated as autosomal dominant in one family and appears uncommon or private; other affected Siberians lacked it. A breed association does not mean every cat of that breed will develop the condition.
- What a positive genetic test means
- A positive result supports cystic-kidney risk for the reported variant. A negative result does not exclude hereditary or acquired renal cysts; renal imaging remains essential.
Relevant breeds/varieties on this page: Siberian
Primary reference for this entry: Lyons LA. Genetic Testing: practical dos and don'ts for cats. J Feline Med Surg. 2024.
Polydactyly
Evidence status: Inherited dominant digit-number trait, usually not a disease by itself
- What it is and how it can affect the cat
- Congenital presence of extra digits, most often on the forepaws.
- How it occurs or is acquired
- Often inherited as a dominant trait and usually does not cause disease by itself. It is common in some Maine Coon lines.
- Inheritance and risk
- Often autosomal dominant with variable expression; different regulatory variants and lineages exist. A breed association does not mean every cat of that breed will develop the condition.
- What a positive genetic test means
- A positive trait result may predict extra digits but does not by itself indicate disability. Examine digit alignment, claw growth and mobility rather than treating genotype as disease.
Relevant breeds/varieties on this page: Maine Coon, Maine Coon Polydactyl
Primary reference for this entry: Merck Veterinary Manual — Commonly reported congenital and inherited defects in cats.
Primary congenital/early-onset glaucoma — LTBP2-related
Evidence status: Established breed/line-associated inherited disorder with a cited molecular test
- What it is and how it can affect the cat
- Inherited abnormality of aqueous-humor drainage that can cause increased intraocular pressure, pain and vision loss.
- How it occurs or is acquired
- This is a germline, usually loss-of-function disorder; it is inherited rather than acquired. Clinical onset and severity remain disorder-specific.
- Inheritance and risk
- Autosomal recessive for the cited breed-associated form. A breed association does not mean every cat of that breed will develop the condition.
- What a positive genetic test means
- For the validated variant, one copy generally identifies a carrier and two copies identify an at-risk genotype. Confirm the exact variant and breed validation before clinical or breeding use.
Relevant breeds/varieties on this page: Oriental Longhair, Oriental Shorthair, Peterbald, Siamese
Primary reference for this entry: Lyons LA. Genetic Testing: practical dos and don'ts for cats. J Feline Med Surg. 2024.
Progressive retinal atrophy — Bengal PRA-b (KIF3B-related)
Evidence status: Established breed/line-associated inherited disorder with a cited molecular test
- What it is and how it can affect the cat
- Inherited retinal degeneration causing progressive vision loss in Bengal cats.
- How it occurs or is acquired
- This is a germline, usually loss-of-function disorder; it is inherited rather than acquired. Clinical onset and severity remain disorder-specific.
- Inheritance and risk
- Autosomal recessive for the cited breed-associated form. A breed association does not mean every cat of that breed will develop the condition.
- What a positive genetic test means
- For the validated variant, one copy generally identifies a carrier and two copies identify an at-risk genotype. Confirm the exact variant and breed validation before clinical or breeding use.
Relevant breeds/varieties on this page: Bengal, Bengal Longhair
Primary reference for this entry: Lyons LA. Genetic Testing: practical dos and don'ts for cats. J Feline Med Surg. 2024.
Progressive retinal atrophy — rdAc (CEP290-related)
Evidence status: Established breed/line-associated inherited disorder with a cited molecular test
- What it is and how it can affect the cat
- Late-onset progressive retinal degeneration leading to blindness.
- How it occurs or is acquired
- This is a germline, usually loss-of-function disorder; it is inherited rather than acquired. Clinical onset and severity remain disorder-specific.
- Inheritance and risk
- Autosomal recessive for the cited breed-associated form. A breed association does not mean every cat of that breed will develop the condition.
- What a positive genetic test means
- For the validated variant, one copy generally identifies a carrier and two copies identify an at-risk genotype. Confirm the exact variant and breed validation before clinical or breeding use.
Relevant breeds/varieties on this page: Abyssinian, American Curl, American Curl Longhair, American Wirehair, Balinese, Bengal, Bengal Longhair, Cornish Rex, Ocicat, Oriental Longhair, Oriental Shorthair, Peterbald, Savannah, Siamese, Somali, Tonkinese
Primary reference for this entry: UC Davis VGL — Progressive Retinal Atrophy (PRA rdAc / CEP290).
Progressive retinal atrophy — Rdy / CRX-related
Evidence status: Established breed/line-associated inherited disorder with a cited molecular test
- What it is and how it can affect the cat
- Early-onset inherited retinal degeneration reported in Abyssinian-family cats.
- How it occurs or is acquired
- This is a germline disorder inherited rather than acquired. Age at clinical expression and penetrance may vary.
- Inheritance and risk
- Autosomal dominant for the cited breed-associated form. A breed association does not mean every cat of that breed will develop the condition.
- What a positive genetic test means
- One validated disease-associated copy can confer risk. A positive result should be interpreted with penetrance, age, phenotype and the exact breed/line in which the assay was validated.
Relevant breeds/varieties on this page: Abyssinian, Somali
Primary reference for this entry: Lyons LA. Genetic Testing: practical dos and don'ts for cats. J Feline Med Surg. 2024.
Pyruvate kinase deficiency — PKLR-related
Evidence status: Established breed/line-associated inherited disorder with a cited molecular test
- What it is and how it can affect the cat
- Inherited erythrocyte enzyme deficiency that can cause intermittent or chronic hemolytic anemia.
- How it occurs or is acquired
- This is a germline, usually loss-of-function disorder; it is inherited rather than acquired. Clinical onset and severity remain disorder-specific.
- Inheritance and risk
- Autosomal recessive for the cited breed-associated form. A breed association does not mean every cat of that breed will develop the condition.
- What a positive genetic test means
- For the validated variant, one copy generally identifies a carrier and two copies identify an at-risk genotype. Confirm the exact variant and breed validation before clinical or breeding use.
Relevant breeds/varieties on this page: Abyssinian, Bengal, Bengal Longhair, Oriental Longhair, Oriental Shorthair, Peterbald, Siamese, Somali
Primary reference for this entry: Lyons LA. Genetic Testing: practical dos and don'ts for cats. J Feline Med Surg. 2024.
Ragdoll HCM — MYBPC3 R820W-associated risk
Evidence status: Validated Ragdoll MYBPC3 R820W susceptibility variant; not diagnostic for HCM
- What it is and how it can affect the cat
- Breed-associated hypertrophic cardiomyopathy risk variant in MYBPC3.
- How it occurs or is acquired
- The R820W variant is associated with HCM risk in Ragdolls; homozygous cats are at particularly high risk. DNA status does not exclude other causes of HCM.
- Inheritance and risk
- Autosomal dominant susceptibility with incomplete, age-dependent penetrance; homozygotes have particularly high risk, while heterozygotes remain variably affected. A breed association does not mean every cat of that breed will develop the condition.
- What a positive genetic test means
- A positive R820W result increases HCM risk in Ragdolls but does not diagnose hypertrophy. A negative result does not exclude HCM; echocardiographic screening remains necessary.
Relevant breeds/varieties on this page: American Bobtail, American Bobtail Shorthair, Highlander, Highlander Shorthair, Ragdoll
Primary reference for this entry: UC Davis VGL — Hypertrophic Cardiomyopathy in Ragdolls.
Scottish Fold osteochondrodysplasia — TRPV4-related
Evidence status: Established TRPV4 fold/osteochondrodysplasia variant with direct welfare significance
- What it is and how it can affect the cat
- Developmental cartilage and bone disorder responsible for the folded-ear phenotype and associated with limb/tail deformity and progressive osteoarthritis.
- How it occurs or is acquired
- The TRPV4 fold variant is autosomal dominant. Folded-ear cats carry the disease-associated variant; homozygous cats tend to be more severely affected.
- Inheritance and risk
- Autosomal dominant with a dosage effect. Folded-ear cats carry at least one associated allele; homozygotes generally develop earlier and more severe skeletal disease. A breed association does not mean every cat of that breed will develop the condition.
- What a positive genetic test means
- One copy identifies a fold-associated osteochondrodysplasia genotype; two copies predict substantially greater risk. Genotype does not measure current pain, deformity or mobility loss.
Relevant breeds/varieties on this page: Scottish Fold, Scottish Fold Longhair
Primary reference for this entry: UC Davis VGL — Scottish Fold TRPV4 test and osteochondrodysplasia.
Spinal muscular atrophy — LIX1/LNPEP-region associated
Evidence status: Established breed/line-associated inherited disorder with a cited molecular test
- What it is and how it can affect the cat
- Inherited motor-neuron disease causing weakness, muscle atrophy and gait abnormalities in young Maine Coon cats.
- How it occurs or is acquired
- This is a germline, usually loss-of-function disorder; it is inherited rather than acquired. Clinical onset and severity remain disorder-specific.
- Inheritance and risk
- Autosomal recessive for the cited breed-associated form. A breed association does not mean every cat of that breed will develop the condition.
- What a positive genetic test means
- For the validated variant, one copy generally identifies a carrier and two copies identify an at-risk genotype. Confirm the exact variant and breed validation before clinical or breeding use.
Relevant breeds/varieties on this page: Maine Coon, Maine Coon Polydactyl
Primary reference for this entry: Lyons LA. Genetic Testing: practical dos and don'ts for cats. J Feline Med Surg. 2024.
Thoracolumbar intervertebral disc disease
Evidence status: Clinical, developmental, conformational or epidemiologic association—not a single diagnostic variant
- What it is and how it can affect the cat
- Degenerative intervertebral disc disease causing spinal pain and/or neurologic dysfunction.
- How it occurs or is acquired
- A referral-population study found Persian and British Shorthair cats significantly overrepresented; this is an epidemiologic association rather than a single-gene disorder.
- Inheritance and risk
- No single universally predictive inheritance model is established for this glossary entry. A breed association does not mean every cat of that breed will develop the condition.
- What a positive genetic test means
- No general positive-DNA-test meaning should be inferred. Use the disorder-appropriate clinical screening, imaging, laboratory testing or phenotypic examination.
Relevant breeds/varieties on this page: British Shorthair, Persian
Primary reference for this entry: Prevalence and breed predisposition for thoracolumbar intervertebral disc disease in cats.
TPO-related inherited hypothyroidism
Evidence status: Established breed/line-associated inherited disorder with a cited molecular test
- What it is and how it can affect the cat
- Inherited thyroid hormone synthesis disorder that can cause poor growth, lethargy and developmental abnormalities.
- How it occurs or is acquired
- This is a germline, usually loss-of-function disorder; it is inherited rather than acquired. Clinical onset and severity remain disorder-specific.
- Inheritance and risk
- Autosomal recessive for the cited breed-associated form. A breed association does not mean every cat of that breed will develop the condition.
- What a positive genetic test means
- For the validated variant, one copy generally identifies a carrier and two copies identify an at-risk genotype. Confirm the exact variant and breed validation before clinical or breeding use.
Relevant breeds/varieties on this page: Russian Blue
Primary reference for this entry: Lyons LA. Genetic Testing: practical dos and don'ts for cats. J Feline Med Surg. 2024.