Mixed-breed cats and inherited diseases

Q: I know mixed-breed dogs can inherit certain genetic diseases. Is the same true for cats? I recently adopted two alley cats, officially called “domestic shorthair” cats, and I wonder if they are susceptible to the same kinds of diseases my purebred cat had.

A: While there’s something to be said for hybrid vigor, it’s also true that mixed-breed cats, who make up the preponderance of our family cats, are susceptible to the same genetic diseases that afflict purebred cats.

The most common inherited diseases in cats are hypertrophic cardiomyopathy, feline lower urinary tract disease, diabetes and inflammatory diseases of the mouth and intestines.

**Hypertrophic cardiomyopathy (HCM)—the most common type of heart disease in cats, is marked by thickening of the walls of the heart. It is difficult to identify early because most cats with HCM appear normal, exhibiting a regular heart rhythm with no heart murmur. HCM becomes apparent when the cat develops heart failure, throws a clot that cuts off circulation to the back legs, or dies suddenly.

**Feline lower urinary tract disease (FLUTD)—an inflammatory disorder of the bladder unrelated to bacteria or viruses. Cats with FLUTD respond to stress by developing bladder pain and bleeding. These cats also have abnormalities in the nervous and endocrine systems.

Feline diabetes—associated with obesity, inactivity and advancing age. Seventy-five percent of diabetic cats are male. Initial clinical signs include increased drinking and urination.

Gingivostomatitis (inflammation of the mouth) and inflammatory bowel disease** (inflammation of the intestines) is inherited in cats, although both conditions rarely occur in one individual. These diseases result from abnormalities in the immune system.

Neither age-related chronic kidney disease nor hyperthyroidism, although common in cats, is thought to be inherited.

Editor’s Note: Both pure bred and mixed breed dogs are susceptible to inherited diseases. Dr. Lee explains the results of a recent study explaining the presence of genes responsible for 152 inherited diseases.

Lee Pickett, V.M.D. practices companion animal medicine. Contact her at askdrlee@insurefigo.com.