An inborn mucopolysaccharide metabolism disorder with iduronate-2-sulfatase deficiency. Clinical characteristics are similar to those in MPS I, except for the absence of corneal clouding and slower progression of the course of disease and central nervous system deterioration. Retinal degeneration may occur, but the cornea usually remains clear. Appearance is normal at birth with excessive growth taking place during first two years of life. Two types are recognized: A severe form (MPS IIA) which is characterized mainly by mental retardation and progressive physical deterioration and early death, and a mild form (MPS IIB) in which patients may survive into adulthood. MPS IIA usually occurs between 2 and 4 years of age with progressive deterioration, chronic diarrhea, recurrent ear infections, hearing impairment, communicating hydrocephalus with increased intracranial pressure, and death at about 10 and 15 years. Obstructive airway disease, cardiac valvular dysfunction, myocardial thickening, pulmonary hypertension, coronary disease, and myocardial infarction may be superimposed. MPS IIB is milder with preservation of intelligence. The symptoms usually include hearing impairment, carpal tunnel syndrome, joint stiffness, discrete corneal opacities, and papilledema. Death may occur in early adulthood, usually from airway obstruction or cardiac failure.