A novel STS mutation and an Xp22.3 microdeletion from one Chinese family with X-linked ichthyosis

Abstract Background X-linked ichthyosis (XLI, OMIM# 308100) is a relatively common type of skin disorder, characterized by widespread, dark brown, polygonal scales and generalized dryness. Most patients (90%) are contributed to genomic deletion of the entire STS (steroid sulfatase) gene encoding steroid sulfatase, with the remaining cases being caused by point mutations or partial deletions. The patient carrying genomic deletion comprising the entire STS gene and adjacent genes often manifests neurological symptoms. Methods Herein, we reported a large four-generation Chinese family with 5 individuals with XLI with/ without mental delay. Genetic analysis was conducted by whole exome sequencing and confirmed by Sanger sequencing and quantitative Real-time PCR. Results These patients present generalized dryness and scaling of the skin with dark scales of the skin on trunk, and limbs. Two pathogenic variants, a novel STS mutation (c.1532A > G, p.E511G, NM_000351) and a ~ 2 Mb genomic microdeletion at Xp22.3 (6,451,785-8,434,424) embracing entire STS gene were identified in this family. In addition, an individual with Xp22.3 deletion has mental delay. Conclusion Our study expands the genetic profile of the STS gene in XLI patients and highlights the clinical application of exome sequencing.