Genetic basis - caused by a nonsense mutation in the ACADVL gene (ACADVL:c.1728C>A), which encodes very long-chain acyl-CoA dehydrogenase (VLCAD). VLCAD is a key enzyme involved in fatty acid beta-oxidation within mitochondria, vital for energy production, especially during prolonged exercise or stress.
Pathophysiology - The mutation truncates the VLCAD protein, leading to enzyme deficiency. Results in impaired fatty acid oxidation, causing defective energy metabolism in muscle cells. Leads to muscle cell damage (rhabdomyolysis) and accumulation of lipids in the muscle fibers. Biochemical effects include increased plasma creatine kinase (CK) and tetradecenoylcarnitine (C14:1) levels.
Complications - Muscle damage from repeated rhabdomyolysis episodes. Risk of permanent disability or death if severe episodes recur. Requires supportive care and lifestyle modifications. No cure; treatment focuses on management and prevention of episodes.
Why This Matters to Breeders and Vets - EIMM is a severe inherited metabolic muscle disorder limiting exercise capacity and quality of life. Genetic testing allows identification of carriers and affected dogs to prevent breeding affected pups. Veterinary understanding of EIMM enables early diagnosis and better management, including avoiding excessive exercise. Helps improve breed health with informed breeding and management strategies.