Prevalence of the myosin-binding protein C mutation in Maine Coon cats

Background: An autosomal dominant mutation has been identified in the myosin-binding protein C (MYBPC3) gene of Maine Coon cats. This mutation changes a conserved amino acid and computationally alters the protein conformation of this gene in Maine Coon cats with hypertrophic cardiomyopathy. The prevalence of this mutation is unknown. Objective: To determine the genetic prevalence of the MYBPC3 mutation in a large cohort of predominantly Maine Coon cats. Animals: Three thousand three hundred and ten DNA samples (blood or buccal swab) from cats. Methods: This retrospective study reviewed the Veterinary Cardiac Genetics Laboratory database at Washington State University for samples submitted for evaluation of the Maine Coon MYBPC3 mutation. The data were analyzed with respect to the breed of cat, mutation status (negative, heterozygous, homozygous), and geographic origin of the submission. Results: In the population of cats studied, Maine Coon cats accounted for 100% of all cats positive for the mutation, and the worldwide percentage of Maine Coon cats carrying the MYBPC3 mutation was 34%. Conclusions and Clinical Importance: The prevalence of the mutation (heterozygous or homozygous) was very similar among countries of submission, suggesting that the 34% mutation rate of the tested samples is a reasonable estimate of the true prevalence of the mutation within the breed. Because of the high prevalence of this mutation, a breeding recommendation to eliminate all cats with the mutation could have a substantial impact on the gene pool. Additional studies are indicated to explore the relationship between genotype and clinical outcome in affected cats.