Rapid laboratory diagnostic of X-linked ichthyosis.

Steroid sulfatase and aryl sulfatase C activities were assayed simultaneously in peripheral blood leucocytes of 4 patients with X-linked ichthyosis (XLI) and 4 patients with autosomal-dominant ichthyosis; 11 healthy subjects served as controls. The deficiency of steroid sulfatase as well as of aryl sulfatase C found in leucocytes of patients with XLI was confirmed by the histochemical demonstration of aryl sulfatase C deficiency in skin sections. Although results are obtained earlier with the histochemical method than with the biochemical assay in leucocytes, several disadvantages brought us to the conclusion that the biochemical assay of microsomal sulfatase activity in leucocytes offers a fast and safe method for the identification of patients with XLI.