Homozygous Nonsense Mutation in SDR9C7 in a Chinese Patient With Autosomal Recessive Congenital Ichthyosis

Abstract

Introduction: Autosomal recessive congenital ichthyosis (ARCI) is a heterogeneous group of cornification disorders. To date, 14 genes have been found to be related to ARCI. We herein describe a patient with ARCI who carried a homozygous nonsense mutation in the SDR9C7 gene and presented with generalized erythroderma, scales, recurrent blisters, and onychomycosis. Case presentation: A 23-year-old woman developed generalized erythroderma and scales over her trunk and limbs shortly after birth, followed by recurrent blisters and nail deformities. A diagnosis of ARCI was made based on her clinical manifestations, family history, and genetic analysis, which revealed a homozygous mutation in SDR9C7 (c.187C>T, p.Q63X). Discussion: Most genes responsible for ARCI are associated with epidermal lipid metabolism, which contributes to the cutaneous barrier. SDR9C7, which encodes short-chain dehydrogenase/reductase family 9C member 7, has also been recently found to play vital roles in this process by regulating ceramide binding to the epidermal cornified cell envelope. For patients clinically suspected to have ARCI, recurrent onychomycosis is a strong indication that they carry a SDR9C7 gene mutation. Conclusion: Remarkable phenotypic and genotypic heterogeneity exists among patients with ARCI. Genetic analysis is an effective tool in diagnosing this and other hereditary diseases. Our patient developed recurrent onychomycosis, a typical presentation of ARCI caused by SDR9C7 mutation, and the unusual blisters further expand the clinical phenotypic spectrum of ARCI.