Steroid-sulfatase deficiency in sex-linked ichthyosis.

Steroid-sulfatase activity was absent in the cultured fibroblasts of nine affected members of eight families with sex-linked ichthyosis. An intermediate value of enzyme activity was found in an obligate heterozygote and a normal value in a patient with ichthyosis vulgaris. Cultured epidermal cells of an affected individual also had no enzyme activity, while normal cultured epidermal cells did.