Whole‐exome sequencing for diagnosis of hereditary ichthyosis

BACKGROUND: Hereditary ichthyosis constitutes a diverse group of cornification disorders. Identification of the molecular cause facilitates optimal patient care. OBJECTIVE: We wanted to estimate the diagnostic yield of applying whole-exome sequencing (WES) in the routine genetic workup of inherited ichthyosis. METHODS: During a 3-year-period, all ichthyosis patients, except X-linked and mild vulgar ichthyosis, consecutively admitted to a university hospital clinic were offered WES with subsequent analysis of ichthyosis-related genes as a first-line genetic investigation. Clinical and molecular data have been collected retrospectively. RESULTS: Genetic variants causative for the ichthyosis were identified in 27 of 34 investigated patients (79.4%). In all, 31 causative mutations across 13 genes were disclosed, including 12 novel variants. TGM1 was the most frequently mutated gene, accounting for 43.7% of patients suffering from autosomal recessive congenital ichthyosis (ARCI). CONCLUSION: Whole-exome sequencing appears an effective tool in disclosing the molecular cause of patients with hereditary ichthyosis seen in clinical practice and should be considered a first-tier genetic test in these patients.