American Shorthair vs Scottish Fold

The 'all-American working cat' story implies a hardy, mixed-heritage constitution, but this is a closed pedigree bred like any other purebred, and Cornell's feline health center lists American Shorthair among the breeds with an elevated rate of hypertrophic cardiomyopathy — the same silent heart disease people specifically worry about in Maine Coons.

Every Scottish Fold's folded ears are caused by osteochondrodysplasia, a cartilage and bone-growth disorder that International Cat Care confirms affects the whole skeleton of every cat that inherits the gene to some degree — this is a genetic disease, not a cute quirk, and it is why major veterinary and welfare bodies consider deliberately breeding for the trait unethical, and why the breed is banned or restricted from breeding in several countries.