Inherited, or genetic, disorders are problems passed on from one generation to the next. There are certain disorders associated with particular breeds; a few major genetic disorders are covered here.
Why do inherited disorders occur?
Inherited disorders result from faults in genes sections of DNA inside cells, which hold the “instructions” for the cat’s development, body structures, and functions. Genetic disorders usually develop in small populations, or result from the mating of animals that are too closely related.
For this reason, such disorders are more common in pedigrees. Sometimes screening tests can be used to identify cats with inherited disorders.
Polycystic kidney disease (PKD) is associated with Persian and Exotic Shorthair cat. It is an autosomal dominant disorder that is, a cat can inherit it from just one parent.
In PKD, a large number of fluid-filled cysts form in the kidneys and gradually increase in size. The disease causes increased urine production, excessive thirst, weight loss, and lethargy. Screening for PKD is possible through DNA analysis of cheek swabs.
Hypertrophic cardiomyopathy (HCM) is mainly associated with the Maine Coon and Ragdoll, and is linked to one faulty gene. The disorder causes the heart muscle to become thicker and less elastic, which reduces the space inside the heart’s chambers and the volume of blood that the heart can pump.
This eventually leads to heart failure. Symptoms of HCM include breathlessness, lethargy, and loss of appetite. Screening involves gene tests and ultrasound scans of the heart.
Hypokalemic polymyopathy This disorder is associated with Burmese, related breeds such as the Bombay and Tonkinese, and Rex cats. An autosomal recessive the disorder is caused by faulty genes from both parents. In hypokalemic polymyopathy, low potassium levels in the blood cause episodes of weak muscles, a stiff walk, and reduced ability to hold up the head. There is a gene test for the disorder; it can be treated with potassium supplements.