Nemaline myopathy is caused by mutations in one of at least 11 different genes. Nemaline myopathy is a clinically and genetically heterogeneous disorder and both autosomal dominant and autosomal recessive forms can occur. Diagnosis is made based upon clinical signs such as muscle weakness, absent or low deep tendon reflexes (hyporeflexia), and a high-arched palate, along with electron-dense aggregates, called nemaline rods, being observed at the microscopic level within muscle fibers. Genetic confirmation through identification of a known genetic mutation in the patient is also an important component of diagnosis.