There are certain health conditions that can be genetically inherited in cats. It is important to understand which breeds of cats are predisposed to which conditions in order to learn about the specific clinical signs you should be aware of in your beloved feline companion. Here are some of the most common genetic conditions in cats:
Polycystic kidney disease
This inherited kidney disease is most commonly diagnosed in Persian cats and Exotic Shorthairs. There is a blood test that can be performed to genetically test for the disease. Polycystic kidney disease is characterized by the development of small, closed, liquid-filled sacs that form in the tissue of the feline kidney. These sacs will continue to grow and multiply leading to eventual fatal kidney failure. Considering it is an inherited disease, some of the small cysts are often present at birth but do not begin to grow at a rapid enough rate to cause abnormal clinical signs until approximately 7 years of age or older. The clinical signs are associated with kidney disease and include increased drinking and urination, decreased appetite, vomiting and lethargy. An ultrasound of the kidneys will allow a veterinarian to make a diagnosis and often treatment is aimed at slowing the progression of kidney failure with fluid therapy, an appropriate diet, and certain medications.
Amyloidosis
Cat breeds such as Siamese, Burmese, Abyssinian, the Oriental Shorthair and certain domestic shorthair have been known to inherit a condition called amyloidosis. Amyloid is a substance composed of abnormally folded protein that is deposited into various tissues and organs of the body, causing malfunctioning of these areas of the body and leading to devastating effects in some cases. Amyloidosis can also be caused by infections, certain cancers or other immune-related conditions. When amyloid deposits are in major organs such as the kidney or liver this can result in severe kidney or liver damage and lead to blood clotting issues. Diagnosis is usually completed by biopsy of certain tissue samples and evaluation of bloodwork and urine testing. Unfortunately, there is no cure for amyloidosis and supportive care is aimed at treating the clinical signs. Fluid therapy, diet changes, and blood transfusions are a few of the possible therapies recommended.
Hypertrophic Cardiomyopathy
This is a heart condition characterized by thickening of the walls of the ventricles of the heart. This thickening leads to a reduced volume of blood that the heart is able to pump during each contraction. There is evidence that the thickening of the ventricles can be related to other diseases such as hyperthyroidism and hypertension, but many of the cases of Hypertrophic Cardiomyopathy is believed to have a genetic basis. Breeds such as Maine Coons and Ragdolls have been studied to have specific genetic mutations predisposing them to develop this condition. Hypertrophic cardiomyopathy, especially if untreated, can lead to heart failure, thromboembolism (clot that forms in a blood vessel and blocks blood flow), hypertension, and occasionally sudden death. Genetic testing and echocardiograms (ultrasound of the heart) are important in identifying cats carrying this condition. Common clinical signs of the condition include coughing, increased respiratory effort, weight loss and a heart murmur on physical examination. Treatment is aimed at helping the heart to function efficiently with medications to relax heart muscle, decrease the heart’s demand for oxygen and control hypertension.
Spina Bifida
Many cats are susceptible to inheriting this genetic condition. The gene mutation in these cats causes the loss or shortening of the tail, spinal cord and certain spinal nerves. This can cause the affected cat to have problems with normal urination and defecation. Severe forms can cause partial or full paralysis of the cat’s back legs. Diagnosis is completed by physical examination and imaging (radiographs, CT). Severe cases are usually untreatable, but in some instances surgery is performed to help with compression or narrowing of the spinal cord.
Polydactyl
This inherited condition in certain cats results in the formation of extra toes. The number of toes can vary in number and also in size and structure. Some toes can be just small pieces of tissues or cartilage while others can be completely functioning digits. The average cat has a total of 18 toes, with five toes of each of the front paws and four toes on the hind paws. Polydactyl cats can have up to eight toes in any of their paws. These cats have fame in Key West because there are approximately 40-50 six-toed polydactyl cats at the Ernest Hemingway Home & Museum. The Guinness Book of World Records lists a cat named Tiger as having the highest number of toes, with 27. Fortunately, these extra toes do not truly pose any serious health issues to cats.