Abstract
A three-year-old male Labrador retriever was presented with five-month history of tetraparesis with severe atrophy in the limbs. Prior to this five-month period, the dog had been healthy. At gross necropsy several muscles were atrophic reflecting decreased muscle mass. Histologically, there were atrophic type I and type II fibres, angulated type IIC fibres and an elevated oxidative activity that showed an altered mitochondrial pattern. The rapid progression of the clinical signs and the age at onset could suggest an atypical myopahty in this dog breed.