Hypertrophic cardiomyopathy (HCM)
A thickening of the heart muscle that can lead to heart failure or sudden death. It has long been reported as inherited in a family of American Shorthairs, and the breed is regularly named alongside Maine Coon and Ragdoll as predisposed. Unlike those two breeds, no breed-validated DNA marker exists for American Shorthair, so genetic testing cannot rule it out.
Qué pedir
No breed-validated DNA test exists — ask for a recent echocardiogram, read by a cardiologist, on both parents

