Analysis of the STS gene in 40 patients with recessive X-linked ichthyosis: a high frequency of partial deletions in a Spanish population.

BACKGROUND: Recessive X-linked ichthyosis (RXLI) (OMIM 308100) is a genodermatosis characterized by polygonal, dark, adherent and mild-to-moderate scales that normally improve during summer. RXLI is caused by a deficiency in steroid sulphatase (STS), whose gene has been located on the X chromosome (locus Xp22.3). Up to 90% of the mutations described in this gene are complete deletions.

OBJECTIVES: Previous reports of partial deletion of STS gene in cases of RXLI prompted us to determine the incidence of these abnormalities in a Spanish population.

METHODS: We have studied exons 1, 5 and 10 of the STS gene by polymerase chain reaction in 40 patients with clinical features of RXLI.

RESULTS: Our results revealed that 30 patients presented complete deletions (75%) while 10 patients had partial deletions (25%) a rate higher than that reported in the previous studies.

CONCLUSIONS: Amplification of exons 1, 5 and 10 is reliable in screening RXLI in the population studied here. No correlation was found between phenotype and the extent of the deletions.