HCM
Hypertrophic Cardiomyopathy is a genetic disease which affects cats, dogs, pigs and people. How it is passed on in generations is still not clearly discovered. Since the 1970's it is known that HCM is the common cause for heart failure, thrombus and sudden death in cats. A major study has been done on Maine Coon cats in the USA which indicates that HCM in these cats seems to be inherited by a single dominant gene.
HCM is characterized by an abnormal thickness of the heartmuscle, mainly at the height of the left side of the heart. Because of the thickening of the heartmuscle the heart becomes less elastic, through which the heart can fill itself less easy. A second consequence is that there is less space for the blood left in the left ventricle, which causes a smaller amount of blood to be pumped around at each heartbeat than normal. The thick heartmuscle can create turbulence in the blood, or the leaking of some valves. This can then cause a heartmurmur, which can be heard by a vet with a stethoscope.
Cats with HCM can get fluid in or around their lungs which can lead to difficult breathing. Other animals may show no signs at all, but they can suddenly drop dead, mostly because of a sudden very severe rhythm disturbance. Some cats develop blood clots that may cause paralysis of the hind legs.
HCM is not a congenital defect, but a disease that develops very slowly. Cats that have HCM very often show no signs before they are six months old, and it can take several years before you can make a diagnosis of HCM. Therefore you must have a specialist performing an echocardiography report on several occasions.
Is there a cure?
Unfortunately HCM can not be cured, but affected cats can be treated with medication. Depending on the symptoms of the animal and the state of the heart, diurectics, beta-receptor antagonists and/or ACE-inhibitors will be used.
How is a HCM test performed?
The cat is examined using an ultrasound machine (echocardiographic test) where you can see if there are any abnormally thickened parts, how the heart beats and how the blood flows.
The examination is painless and is usually tolerated very well by the cats. If the cat feels uneasy, it would be better giving the cat a slight sedation (injection) as it is important that the cat lies still on the examination table.
Sometimes it is necessary to shave the cat a little just on the spot where it is going to be examined. In other cats it works very well just spreading the fur apart without having to shave. In order to get good contact with the cat’s skin and also a good picture of the examined area jelly is being used. The examination lasts for about 30-40 minutes.
I'm testing my cats on a yearly base for HCM and publish the results of my cats at www.ragdolldatabase.nl
http://www.andie.org.uk/hcm/index.htm
PKD
Polycystic kidney disease (PKD) is an inherited condition that causes multiple cysts (pockets of fluid) to form in the kidneys. These cysts are present from birth. They start out very small but they grow larger with time and may eventually severely disrupt the kidney; when that happens the kidney can no longer work and kidney failure develops. The cysts usually grow quite slowly, so most affected cats will not show any signs of kidney disease until relatively late in life, typically at around seven or eight years old. However, in some cats kidney failure will occur at a much younger age and at the moment there is no way of predicting how rapidly the disease will progress in any particular cat.
Unfortunately PKD has now become very common in some cat breeds. Persians and Exotic Shorthairs have the highest incidence of problems and studies around the world have shown that around one in three cats from these breeds are now affected by the disease. Other cat breeds that have been developed using Persian bloodlines, and breeds that have allowed outcrossing to Persian cats (eg British Shorthairs) may also have a proportion of affected cats, but in other unrelated breeds it is an extremely rare condition.
How is PKD inherited ?
PKD is the result of a single, autosomal, dominant gene abnormality. This means that:-
Every cat with the abnormal gene will have PKD; there are no unaffected carriers of the gene.
Every cat with PKD will have the abnormal gene, even if that cat only has a few small cysts in its kidneys.
A cat only needs one of its parents to be affected with PKD in order to inherit the abnormal gene.
Every breeding cat with PKD will pass the disease on to a proportion of its kittens, even if it is mated with an unaffected cat.
It appears that inheriting two copies of the abnormal gene, ie, one from each parent, causes such severe disease that the affected kitten dies before birth. All affected cats are therefore considered to be heterozygous (ie they carry one PKD gene and one normal gene).
Can PKD be cured ?
Unfortunately there is no available treatment that will prevent the development of kidney failure in a cat that is affected by PKD. The cysts are present from birth and cannot be removed, nor can they be prevented from growing.
Once kidney failure has actually developed, treatment can be used to try to reduce the amount of work that the kidneys have to do, and to try to reverse the secondary effects of renal failure. Such treatment will improve the cat's quality of life, but will not alter the underlying disease or stop the cysts from growing larger.
A kidney with PKD
Do all cats with PKD die of renal failure ?
The number of cysts present in each kidney, and the rate at which the cysts grow, varies considerably from cat to cat. Severely affected cats or cats with rapidly growing cysts will develop renal failure at an early age, and will die from PKD. Most affected cats wil appear to be quite healthy until later in life. but will eventually succumb to renal failure and die from PKD. Some cats with few cysts or slowly growing cysts may remain healthy into old age, and may die from other conditions before renal failure develops.
Unfortunately there is currently no way to predict how quickly the condition will progress in an individual cat, and at what age renal failure will occur.
What can be done about PKD ?
All cats that carry the abnormal gene are affected with PKD, and affected cats can be identified before they reach breeding age. This makes it relatively easy to eliminate the disease from a breeding group; if all cats in the high-risk breeds were to have their kidneys scanned or be gene tested before they were used for breeding, and if affected cats were not then used for breeding, then PKD could be eradicated from those breeds in a single generation.
There is a DNA-test for PKD, but it hasn't been validated for the Ragdoll.
Source: http://www.fabcats.org/pkd.html