Renal Dysplasia

Definition of Renal Dysplasia

Dysplasia is defined generally as an abnormality of development in which the adult cells and tissues are abnormal in size, shape, organization and/or function. Renal means pertaining to the kidneys. Renal dysplasia, then, is defined as a developmental abnormality of one or both. It usually is characterized by small, misshapen kidneys at the time of birth that do not mature normally in terms of size, shape, organization and/or function. This is a congenital kidney disorder – one that is present at birth.

Causes of Renal Dysplasia

Renal dysplasia can be caused by several different things, although the exact causes are not well-understood. Some authorities suggest that renal dysplasia may be caused by bacterial or viral infection of fetal tissues as they develop inside the mother’s uterus (this is called intrauterine fetal infection). Canine herpesvirus has been reported as one potential cause of intrauterine fetal viral infections. Another possible cause is the mother’s ingestion of or exposure to toxins, or physical trauma to the fetus, during the course of the pregnancy.

In addition, there are a number of hereditary defects in kidney development that have been seen in domestic dogs. These tend to occur more commonly in certain breeds. Some dogs inherit renal dysplasia as a result of what is referred to as an autosomal recessive gene. This means that affected dogs can be of either gender, and that both parents are either carriers of the gene or are themselves affected with the disorder. In Samoyeds, renal dysplasia is reportedly caused by what is called an X-linked trait, which means that many more males than females develop clinical symptoms of the disease.

Prevention

According to most experts, dogs known or suspected to have renal dysplasia should not be part of any responsible breeding program, given the strong genetic component associated with this disorder. Repeated breedings of the parents of affected puppies probably should be avoided, as well.

Special Notes

Puppies are not born with fully mature kidneys. In fact, significant development, maturation and microscopic cellular changes in the kidneys occur during the first two to three months of a dog’s life. After that time, biopsies of kidney tissue should appear normal when examined under a microscope, through a process known as histology or histopathology.