Hunter syndrome

Alternative names:

mucopolysaccharidosis type II

Definition:

A hereditary storage disease in which the of a mucopolysaccharide in body tissues results in damage.

Causes, incidence, and risk factors:

Hunter syndrome is inherited as an X-linked disease. Females with one normal X and one defective X chromosome are disease free. Males with a defective X chromosome develop Hunters syndrome. The metabolic abnormality that causes Hunter syndrome is a lack of the enzyme iduronosulfate sulfatase. In its absence mucopolysaccharides collect in various body tissues causing damage.

Affected children may develop an early onset type (A) shortly after 2 years that causes a large skull, coarse facial features, profound mental retardation, spasticity, stiffness, and aggressive behavior. A late onset type (B) that causes much milder symptoms.