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. Pathologic examination reveals neuronal atrophy in the globus pallidus and iron deposition in blood vessels and perivascular spaces. (From Adams et al., Principles of Neurology, 6th ed, p972; Davis & Robertson, Textbook of Neuropathology, 2nd ed, pp972-929).