Hereditary or genetic diseases do not spare cats any more than humans. We mustachioed companions are all the more subject to it as men have made selections on aesthetic criteria, to give birth to “purebred cats”.
Today, successive selection strategies have existed for more than two centuries and have intermingled purebred cats and alley cats. The entire feline population, with or without pedigree, is therefore affected by hereditary diseases.
Single Or Multifactorial Hereditary Diseases
Using more scientific terms, two main types of hereditary diseases are to be distinguished. On the one hand monogenic (or simple) diseases determined by a single gene, and on the other polygenic (or multifactorial) diseases determined by several genes.
The use of genetics makes it possible to classify simple hereditary diseases and even to predict them statistically in a litter of kittens. Multifactorial hereditary diseases, on the other hand, are more difficult to predict and identify.
The Most Well-Known Hereditary Diseases Of Cats
In this article, we focus on the most well-known hereditary diseases of cats. These are the most frequently encountered monogenic diseases, but also those that can be diagnosed through the use of a DNA test.
Polycystic Kidney Disease (Pkd)
This hereditary disease mainly affects Persian and related cats (Exotic Shorthair, British Shorthair, etc.). Called PKD in English for Polycystic Kidney Disease, polycystic kidney disease, as its name suggests, is a disease that manifests itself by the progressive appearance of cysts in the kidneys of the affected cat.
The older the cat, or the more it is affected by PKD, the more the cysts multiply and grow, leading to chronic renal failure. The symptoms that accompany this hereditary disease are vomiting, diarrhea, weight loss and listlessness.
The mode of inheritance of PKD is autosomal dominant. This means that the kitten with PKD has at least one parent carrying the mutated gene (PKD1 gene). There is no treatment to date against the disease and it can appear at any age.
Hypertrophic Cardiomyopathy (Hcm)
This disease is transmitted in the same way as PKD, via the mutated MYBPC3 gene. It mainly affects Maine Coon and Radgoll breed cats. Called Hypertrophic Cardio Myopaty in English, hypertrophic cardiomyopathy results in health problems affecting the heart.
It generally goes unnoticed until the first symptoms appear, including exercise intolerance, heart murmur or dyspnea. The development of the disease leads to acute heart failure with arrhythmias, pulmonary edema, arterial thrombosis, cardiac arrest and sudden death.
Glycogen Storage Disease Type Iv (Gsd-Iv)
It is a rare but unfortunately fatal genetic disease that only affects the Norwegian OR Skogcatt cat. It is autosomal recessive and is due to the GBE1 gene. This means that an adult cat can be a healthy carrier and pass it on to its offspring.
The survival rate of the kittens is then low, but some survivors can do well until the age of 6 months maximum. Glycogen is then no longer transformed into sugar by the body and invades the cells and organs of the kitten. This is followed by muscle atrophy, generalized weakness and inevitably death.
The affected cat has a very limited life expectancy, not exceeding one year in most cases.
Neonatal Erythrolysis (Ni)
It is a common cause of death in kittens only a few days old. This disease is, fortunately, preventable if we know how to recognize the first symptoms quickly.
It can affect all breeds of cat even if some are more predisposed than others, such as the Abyssinian, the Birman, the British Shorthair, the Chartreux, the Persian, the Rex Cornish, the Rex Devon or the Sphynx.
Neonatal erythrolysis is caused by the CMAH gene and is due to incompatibility between blood groups. If the female is group B and transmits antibodies A via colostrum to her group A kitten, these will destroy the kitten’s red blood cells, which can die in a few hours or a few days.
Symptoms are blood in the urine, jaundice, necrosis of the extremities and cessation of breastfeeding. By isolating the kitten from its mother via another nursing cat or bottle-feeding, neonatal erythrolysis is avoided.
Progressive Retinal Atrophy (Pra)
PRA or progressive retinal atrophy is, as its name suggests, an inherited disease resulting in progressive degeneration of the retina, up to blindness which usually occurs at the age of 3 or 5 years.
It is an autosomal recessive disease caused by the CEP290 gene which affects many cat breeds: Abyssinian, American Curl, American Wirehair, Balinese, Bengal, Cornish Rex, Munchkin, Siamese, Tonkinese, etc.
Although it does not lead to the death of the cat, it remains a handicap for this predator and excellent hunter. It is not possible to predict whether a carrier kitten will develop the disease, nor is there a treatment to delay its onset.
Spinal Muscular Atrophy (SMA)
Known as SMA, spinal muscular atrophy is also an autosomal recessive hereditary disease caused by the LIX1 gene. It only affects the Main Coon breed. The first symptoms appear in the kitten from its 3 or 4 months and are identical to those developed by humans for the same disease.
This is followed by slight tremors, an abnormal gait visible on the hind limbs, then muscle weakness and sometimes great difficulty in moving. There is no curative treatment.
How To Avoid Feline Hereditary Diseases?
Known hereditary diseases are not inevitable. They can be limited or even eradicated thanks to a program of repopulation of an adequate race, without losing the characteristics which make its beauty.
Limit Inbreeding As Much As Possible
Inbreeding inevitably reduces the richness of the genetic heritage and accelerates the appearance of hereditary diseases. It increases so-called recessive diseases when these can be controlled.
This involves the use of systematic DNA tests for all individuals of the same race. It is then advisable to make marriages by avoiding any consanguinity (particularly if it is at risk) to eradicate the known hereditary diseases.
Promote Interbreeding As Soon As Possible
To increase the genetic heritage and diversify it, it is useful to introduce new individuals to promote interbreeding and the health of purebred cats. By favoring marriages with individuals of other similar breeds, or simply mating with healthy alley cats, we give back to the purebred cat the diversity it needs for a good development.
The individuals closest aesthetically to the breed concerned can thus be kept in the line, while the others will be discarded. But the health of all individuals will be improved thanks to this genetic mixing.
Require Dna Testing For Cats Prone To Genetic Diseases
Well-known genetic diseases affect some breeds more than others. Kittens and adult cats are purchased from a breeding farm that must do all the DNA tests before resale. Some diseases are also classified as red hibitory or “hidden defects”.
You can inquire with the LOOF (Official Book of Feline Origins) before adopting a purebred cat to find out the hereditary diseases to which it is subject and require the seller to carry out genetic tests before purchase. If not, do not hesitate to consult your veterinarian to have your cat tested as soon as possible.