Renal dysplasia belongs to the group of common familial kidney disorders in cats and dogs that includes renal amyloidosis, renal dysplasia, polycystic kidney disease, basement membrane disorders, and Fanconi syndrome.
Renal Dysplasia is a genetic disease that affects the kidneys which become small and pale and are unable to function properly. The functional kidney units called nephrons do not mature and remain at their infantile stage until they fail. This loss of nephrons is "silent" because it can go on for months or years without causing any signs. Only when two-thirds of nephrons have been destroyed are there the beginning of the clinical signs.
The early stage, called compensated renal insufficiency, is marked by excessive thirst and increased urination. When three-quarters of nephrons are gone, affected dogs are in renal failure. The kidneys can no longer filter toxins from the blood and the affected dogs are physically ill from the poison.
The most severely affected dogs have problems by eight weeks of age. They die shortly thereafter. Mildly affected individuals may make it to six months of age before having problems. The most devastating cases to the breed are those that are only minimally affected and live long enough to contribute their defective genes to future generations. Blood test such as urea (blood urea nitrogen) and creatinine will only detect kidney problems when 75% or more of the kidney capacity is lost. The definitive diagnosis of renal dysplasia requires biopsy.
Although some medications can relieve the pain and suffering of the dog, there is no cure for renal failure. Dialysis can be done, but it is expensive and typically buys only a small amount of time. A low-protein diet that is rich in specific amino acids and low in phosphates is the best nutritional approach for mildly affected individuals. Breeders should test their puppies as early as eight weeks.