Journal of Veterinary Internal Medicine
Volume 24, Issue 3, pages 527-532, May/June 2010
Association of A31P and A74T Polymorphisms in the Myosin Binding Protein C3 Gene and Hypertrophic Cardiomyopathy in Maine Coon and Other Breed Cats
Background: Hypertrophic cardiomyopathy (HCM) is an inherited autosomal dominant trait in cats. The A31P single nucleotide polymorphism (SNP) in the myosin binding protein C 3 gene is thought to be the causative mutation in Maine Coon cats. Additionally, the A74T SNP is offered as a genetic test for HCM.
Objectives: To evaluate the genetic association between the above-mentioned SNPs and phenotypes.
Animals: Eighty-three Maine Coon cats and 68 cats of other breeds.
Methods: The study was performed prospectively. Cats were phenotyped as healthy or HCM with echocardiography. Taqman genotyping assays were used for genotyping; results were confirmed by sequencing analysis.
Results: A31P was found in 18/83 (22%) Maine Coon cats.
Fifteen of 18 Maine Coons (83%) with the A31P mutation were healthy on
echocardiographic examination (mean age 65 months). A74T was present in 28/79
(35%) of Maine Coons and in 42/68 (62%) of other cat breeds. Twenty-two of 28
(79%) of Maine Coons and 21/42 (62%) of other breed cats with the A74T mutation
were healthy at a mean age of 72 months and 91 months, respectively. Of 12 Maine
Coons with HCM, 9 (75%) were genotype-negative for A31P and 6 (50%) for A74T.
Allele frequencies did not differ significantly (P= .47) between phenotype
groups. None of the evaluated genetic tests was able to provide useful
predictive information of disease outcome.
Conclusions and Clinical Importance:
The value of currently available genetic tests is low in the cats of this study. The mutations analyzed appear to have a low penetrance, and even homozygote cats can remain healthy.