Tales from the Pet Clinic

Nearly everything about us and our cats is determined by a molecule called DNA (deoxyribonucleic acid).   Due to the wonders of molecular genetics, DNA has been harnessed as a method of diagnosing diseases in our feline companions.  Because members of a breed are closely related, genetically based diseases are often first identified in a family of purebred cats.  Purebred cats, such as those you can meet at the 2011 “AKC Meet the Breeds” show at the Javits Center in New York City on November 19 and 20, have contributed to the advancement of DNA testing – testing benefitting all cats.

DNA and Disease

Ragdoll and Maine Coon cats may both develop cardiomyopathy, a disorder of the heart muscle causing the muscle to become very thick and resulting in heart failure.  Analysis of the DNA in these two breeds has identified mutations associated with the development of hypertrophic cardiomyopathy.  Breeders often use this test to help select the healthiest cats to parent future litters of kittens.  The AMC’s Cardiology Service does not use this test to predict the development of cardiomyopathy because all cats with the mutation do not go on to develop this type of heart disease.  The AMC’s staff cardiologists, Dr. Betsy Bond and Dr. Philip Fox, perform echocardiography to diagnose cardiomyopathy in cats.

The red blood cells of the Abyssinian cat and its cousin, the Somali, are affected by a genetic disease called pyruvate kinase deficiency.  The enzyme pyruvate kinase can be found in the biochemical pathway responsible for providing the red blood cell with energy.  Cats lacking this enzyme have weak red blood cells.  The shortened survival of these weakened red blood cells renders affected cats sick and anemic.  Domestic cats have also been diagnosed with this genetic disease.

Chronic upper respiratory infections and chronic diarrhea result from infection with a variety of organisms. DNA testing can be used to determine the cause.  DNA testing identifies the presence of DNA belonging to a disease-causing virus, bacteria, parasite or mycoplasm, thus determining the cause of infection and directing therapy.

Conducting DNA Testing

DNA testing can be performed on a variety of samples.  The sample submitted to the laboratory by your veterinarian will depend on the test being performed.  If the test is looking for a mutation in your cat’s DNA as the cause of a disease, cardiomyopathy, for example, the sample must contain your cat’s DNA.  Cheek swabs and blood samples are typically submitted for this type of test.  If your veterinarian is looking for an infectious organism, the site of the infection might be sampled.  A conjunctival swab can be used to detect feline upper respiratory viruses; feces can be used to identify the causative agent of diarrhea.  Some tumors carry genetic mutations and the actual tumor sample is submitted to the laboratory to identify the mutation and the type of tumor.

Meet Purebred Cats

To meet all the purebred cats I have highlighted in the blog and more, join us at the 2011 “AKC Meet the Breeds” show at New York City’s Javits Center on November 19-20.  Billed as an event where families can meet 160 dog breeds and over 50 cat breeds, the event promises to have something for everyone. Don’t miss this great opportunity to meet wonderful purebred cats, ask questions about them, and learn which one is the best one for your family.  Stop by The Animal Medical Center booth to say hi! You can meet some of the staff and veterinarians who work with us and ask questions about your cat’s health.