ABSTRACT
Patients with C. Hunter disease present a broad spectrum of clinical activity; all of them have quite similar reduction in enzyme activity. Patients with the severe form of Hunter disease have the characteristic coarse features of mucopolysaccharidosis. Hunter factor was identified as iduronate sulfatase, the enzyme that catalyzes the release of sulfate from the iduronate sulfate moieties of dermatan and heparan sulfates. The enzyme, which removes the sulfate from the 2-position of iduronic acid, is essential for the sequential degradation of heparan sulfate, which contains many sulfated iduronic acid residues, and dermatan sulfate, which contains a smaller number of such residues. Prenatal diagnosis has also been accomplished by assay of the enzyme in chorionic villus homogenates. In the case of female fetuses, very low levels of enzyme may be found in either amniocytes or chorionic villus cells; therefore, it is important that karyotyping be carried out in all instances.
