Genetics: Sphynx Hypertrophic Cardiomyopathy (HCM)
Sphynx hypertrophic cardiomyopathy (HCM) usually does not show up until they are an adult although the genetic mutation is present at birth.
Sphynx Cat Hypertrophic Cardiomyopathy (HCM) Testing Price: $40.00 per cat, or $25 per kitten for two or more kittens from the same litter
Sphynx hypertrophic cardiomyopathy (HCM) usually does not show up until they are an adult although the genetic mutation is present at birth. The age of presentation of disease is variable with many cats developing the disease between 2-3 years of age and some developing it much older (8 -10 years of age).
We identified a DNA mutation in about 60% of affected Sphynx Cats. This mutation is also found occasionally in healthy adult Sphynx cats who do not have the disease. This referred to as “incomplete penetrance”. This means that even if a cat has the genetic mutation, the mutation may not actually penetrate or lead to the development in full disease in that cat. This is also a common finding in Maine Coons, Ragdolls and human beings with genetic mutations associated with Hypertrophic cardiomyopathy.
Importantly since this mutation only appears to have identified about 60% of affected cats, it appears likely that there is at least one other Sphynx cat HCM Mutation.
DNA test results will indicate if the cat has the mutation on 1 copy of its 2 gene copies (called heterozygous) or both gene copies (homozygous). At this time, we do not know if the risk of developing disease is higher in cats that are homozygous for the mutation than heterozygous.
Once you run the DNA test we will send you results that state your cat’s results are either:
- Negative – This means that your cat does not have the genetic mutation for Sphynx HCM. However, this does not mean that your cat can never get HCM since there may be other causes of the disease; it means that it will not get HCM from the known Sphynx DNA mutation.
- Positive Heterozygous – This means that your cat has 1 copy of the genetic mutation and 1 copy of a normal gene. Breeding recommendations: At this time, we do not recommend withholding all positive heterozygous cats out of the breeding program. Since many cats that are positive heterozygous may not get sick from the disease it may be reasonable to consider breeding these cats to a Negative cat, screening the kittens and trying to select a Negative kitten to keep as a replacement breeding animal in the next litter or so. We would never recommend breeding a positive heterozygous cat to a positive heterozygous cat since this could produce homozygous cats, which will most certainly pass on the mutation.