Two novel SASH1 mutations in Chinese families with dyschromatosis universalis hereditaria

Dyschromatosis universalis hereditaria (DUH) is a rare genodermatosis characterized by hyper- and hypo-pigmented macules on the face, trunk, and extremities. The condition causes severe cosmetic problem which can lead to significant psychological distress to the patients and bear a negative impact on society. DUH is a condition with genetic heterogeneity. The SASH1 gene was recently identified as pathogenic genes in DUH patients.

Two families clinically diagnosed with dyschromatosis universalis hereditaria were enrolled. Whole-exome sequencing combined with Sanger sequencing and bioinformatics analysis was performed in the probands. MutationTaster, CADD, SIFT, PolyPhen-2, and LRT software, and The American College of Medical Genetics and Genomics Standards and Guidelines were employed to assess the pathogenicity of detected missense mutations. One hundred healthy unrelated Chinese individuals were used as controls. All participants signed an informed consent form.

Genetic screening revealed a heterozygous SASH1 c.1547G>A (p.Ser516Asn) mutation for patients in family 1, and SASH1 c.1547G>T (p.Ser516Ile) for family 2. Both such de novo mutations are located in a highly conserved SLY domain in SASH1, have not been previously reported in any publication, and were not detected in any control databases.

The novel heterozygous mutations, SASH1 c.1547G>A and c.1547G>T, are likely responsible for the DUH phenotype in these two families. Our study expands the mutation spectrum of DUH. Whole-exome sequencing showed its efficiency in the diagnostic of hereditary skin disorders.