Dog hereditary diseases
Dog hereditary diseases
Canine degenerative myelopathy (DM) is a severe, progressive neurodegenerative disease that causes paralysis of the hind limbs and is common in some dog breeds. The disease is caused by dysfunction of the spinal cord motor neurons due to degeneration (simplification) of their nerve endings. Degenerative myelopathy was first described over 35 years ago as a spontaneously occurring disease of the spinal cord in adult dogs. It was believed to be specific only to the German Shepherd breed, which is why it was also called German Shepherd myelopathy. Later, the disease was detected in a number of breeds - Welsh Corgi Pembroke, Boxer, Rhodesian Ridgeback, Chesapeake Bay Retriever.
The first signs of the disease appear already in adult dogs, most of them at the age of 8-14 years. The earliest manifestation of degenerative myelopathy begins with almost imperceptible weakness in one or both hind limbs. Over time, you can hear the so-called "shuffling" of the claws of the hind legs on the asphalt. The dog has some difficulty getting up from a sitting or lying position. Loss of balance appears. The dog's tail becomes "inactive", its mobility is lost. If the tail is long, it can get tangled in the dog's legs. Also, in the initial stages, the animal experiences a loss of coordination, after which ataxia of the hind limbs develops. The duration of the disease in most cases does not exceed three years. In the last stages of myelopathy, the dog has practically no hind limb reflexes, and paralysis sets in. Then the disease spreads to the forelimbs. At the same time, signs of damage to the upper motor neurons appear, which leads to ascending paralysis of all limbs and general muscle atrophy. Complete paralysis of the dog's limbs sets in. Due to the fact that many diseases of the spinal cord can have similar clinical signs, without DNA testing, the final diagnosis of degenerative myelopathy can only be made posthumously after histological examination.
A genetic test (DNA test) has been developed to diagnose the disease, which can be performed at any age. A DNA test allows you to detect the presence / absence of a mutant (defective) copy of a gene leading to a given disease. Since degenerative myelopathy is characterized by an autosomal recessive inheritance pattern, the patients will be animals homozygous for the mutant copy of the gene. To date, there is no medical or surgical treatment for DM, so it becomes very important to know if a dog carries a mutant copy of the gene. DNA testing will reduce the frequency of sick dogs being born. Since this serious disease occurs only in adult dogs, it is possible to make a preliminary diagnosis by determining the genotype only with the help of genetic research.
Autosomal recessive inheritanceARMM - sickNM - healthy, carrierNN is healthy