Maine Coon — questions to ask before paying a deposit
A responsible breeder will have these readily available. Deflection is a red flag.
Hypertrophic cardiomyopathy (HCM) — MYBPC3 A31P variantcan shorten life or cause chronic pain
A mutation in the MYBPC3 gene thickens the heart muscle and can cause sudden cardiac death. It is found only in Maine Coons (not in other pedigree breeds), at roughly 30-40% carrier prevalence in some populations. Penetrance depends heavily on genotype: cats with two copies have high penetrance — almost all develop HCM by 5 years old — while cats with a single copy carry a much lower and later risk, so the two results are not equivalent.
Ask to see: UC Davis VGL Maine Coon HCM DNA test (MYBPC3 A31P) on both parents. The mutation does not explain all HCM in the breed, so a clear DNA result does not replace periodic cardiac ultrasound (echocardiogram) of the breeding cats.
UC Davis VGL — Hypertrophic Cardiomyopathy (HCM) in Maine Coons (https://vgl.ucdavis.edu/test/maine-coon-hcm) · PMC — Genotype-phenotype correlation between cMyBP-C A31P and HCM in a cohort of Maine Coon cats (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3044103/)
Spinal muscular atrophy (SMA)can shorten life or cause chronic pain
A recessive loss of motor neurons in the lower spinal cord. Affected kittens are normal at birth and develop unsteady gait and hind-limb muscle wasting from around 3-4 months old. It does not shorten life, but it is a permanent, disabling condition.
Ask to see: UC Davis VGL Maine Coon SMA DNA test on both parents.
UC Davis VGL — Spinal Muscular Atrophy (SMA) in Maine Coon Cats (https://vgl.ucdavis.edu/test/maine-coon-sma)
Hip dysplasia
Malformation of the hip joint causing laxity, pain and early osteoarthritis. Documented at roughly 25-37% prevalence in OFA-screened Maine Coons, worsening with age and body mass. There is no single-gene DNA test — it is polygenic and diagnosed by radiograph.
Ask to see: Hip radiographs scored by OFA (a grade) or PennHIP (a laxity measurement) on both parents — not a DNA test.
PMC — Demographics of hip dysplasia in the Maine Coon cat (https://pmc.ncbi.nlm.nih.gov/articles/PMC11129213/) · PMC — Demography, heritability and genetic correlation of feline hip dysplasia and response to selection in a health screening programme (https://pmc.ncbi.nlm.nih.gov/articles/PMC6868272/)
Erythrocyte pyruvate kinase (PK) deficiency
A recessive enzyme defect causing intermittent haemolytic anaemia, with highly variable age of onset and severity. Maine Coon is one of the breeds UC Davis names as appropriate for this test.
Ask to see: UC Davis VGL PK deficiency DNA test on both parents.
UC Davis VGL — Erythrocyte Pyruvate Kinase Deficiency (PK Deficiency) (https://vgl.ucdavis.edu/test/pk-deficiency-cat)