Congenital Adrenal Hyperplasia is a disorder that occurs when a cytochrome P450 adrenal enzyme (11b-hydroxylase) is rendered ineffective by the mutation. This results in inadequate glucocorticoid production by the adrenal glands. The clinical signs are caused partially by the inadequate cortisol levels in the body as well as from the impact of complex effects on hormonal feedback mechanisms. Kittens affected by the disease have high blood pressure and urinate and drink excessively. Other clinical signs include genital abnormalities, early male puberty, presence of secondary sex characteristics post-neutering, small body size, greasy coat, and thickened skin. Affected cats may show behavioral abnormalities (such as intercat aggression).

Lifelong corticosteroid therapy is commonly used for treatment of Congenital Adrenal Hyperplasia and results in improvement of most clinical signs. Routine monitoring is required to ensure adequate dosing of corticosteroids and to monitor for potential side effects of chronic corticosteroid therapy.

There are many responsibilities to consider when breeding cats. Regardless of test results it is important that your cat is in good general health and that you are in a position to care for the kittens if new responsible owners are not found. For first time or novice breeders, advice can be found at most cat registry websites.

This disease is autosomal recessive meaning that two copies of the mutation are needed for disease signs to be shown. A carrier cat with one copy of the CAH mutation can be safely bred with a clear cat with no copies of the CAH mutation. About half of the kittens will have one copy (carriers) and half will have no copies of the CAH mutation. Kittens in a litter which is expected to contain carriers should be tested prior to breeding. Carrier to carrier matings are not advised as the resulting litter may contain affected kittens. Please note: It is possible that disease signs similar to the ones caused by the CAH mutation could develop due to a different genetic or clinical cause.