MSH: A rare autosomal recessive degenerative disorder which usually presents in late childhood or adolescence. Clinical manifestations include progressive MUSCLE SPASTICITY; hyperreflexia; MUSCLE RIGIDITY; DYSTONIA; DYSARTHRIA; and intellectual deterioration which progresses to severe dementia over several years. (From Adams et al., Principles of Neurology, 6th ed, p972; Davis & Robertson, Textbook of Neuropathology, 2nd ed, pp972-929),NCI: A rare autosomal recessive inherited disorder caused by mutations in the PANK2 gene. It is characterized by abnormal accumulation of iron in the basal ganglia. Signs and symptoms include progressive motor disturbances, muscle spasm and rigidity, dysarthria, mental deterioration, and behavioral changes.,NCI: A rare neuroaxonal dystrophy, histologically characterized by axonal spheroids, iron deposition, lewy body (LB)-like intraneuronal inclusions and neurofibrillary tangles.