Novel mutation in the DSG1 gene causes autosomal-dominant striate palmoplantar keratoderma in a large Syrian family

Palmoplantar keratoderma (PPK) is a heterogenous group of skin disorders characterized by a persistent thickening of the palms of the hands and sometimes soles of the feet. PPK can be classified into many types, including diffuse, transgradient, and focal or striate, where the areas of palmoplantar skin are alternatively thickened. Mutations in four main genes, keratin 9 (KRT9), keratin 1 (KRT1), desmoglein (DSG1), and desmoplakin (DSP), have been associated with PPK. Striate PPK (SPPK) is commonly caused by mutations in DSG1. However, DSP and KRT1 gene mutations have been identified in some cases. In this study, fragment and sequencing analysis were performed for a large Syrian family with dominant SPPK. Segregation analysis showed a linkage with DSG1 gene. Direct Sanger sequencing identified a new mutation c.dup165_168AGCA. This frameshift mutation was heterozygous in all affected family members and absent in all normal individuals.