STEROID SULFATASE DEFICIENCY IN JAPANESE PATIENTS - CHARACTERIZATION OF X-LINKED ICHTHYOSIS BY USING POLYMERASE CHAIN-REACTION

X-Linked ichthyosis (XLI) due to deficiency of steroid sulfatase (STS) of which gene consists of 10 exons is an inherited skin disorder. The gene, mRNA and protein of STS were examined in six Japanese patients with XLI. Neither the mRNA nor the enzyme protein was detected in a pa tient. The results of Southern analysis using STS cDNA as a probe indi cated that all the patients examined exhibited large deletions of the STS gene. When exon 1 and the exon 10 of the STS gene were amplified b y polymerase chain reaction using patients' genomic DNA as templates, no product was detected in all the patients examined. These observatio ns suggest that most XLI in Japanese patients is caused by an extensiv e deletion of the STS gene as was demonstrated in Caucasian patients. The PCR method in the present study is useful for the diagnosis of XLI in prenatal and postnatal subjects.