MODEL RELEASED. Myopathy research. Myopathy researcher pipetting liquid into multiwell trays containing cell cultures. Myopathies are a group of neuromuscular diseases in which the muscle fibres do not function properly, resulting in muscular weakness. Myopathies may be autoimmune, where the body's immune system attacks the muscles, due to metabolism defects, or congenital (present from birth). Photographed at the French Association for Combating Myopathy (AFM).