The STS gene is located in the chromosomal region Xp22.32. This gene encodes the enzyme steroid sulfatase, which catalyzes conversion of sulfated steroid precursors into estrogens during pregnancy. The protein is located in the endoplasmic reticulum in the form of homodimer. Mutation in the STS gene is clear evidence of the X-linked recessive ichthyosis (XLRI), which is often hardly clinically distinguished from ichthyosis vulgaris. Pathogenesis of the XLRI is caused by an increased amount of cholesterol sulfates in the epidermis inhibiting serine proteases. As a result, the delayed desquamation of corneocytes occurs. Most patients with X-linked recessive ichthyosis (85-90%) carry a large deletion in the STS gene.
For the purpose of the examination of large deletions and duplications of the STS gene, we use the SALSA MLPA kit P160 STS of MRC Holland company.
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