Autosomal Recessive Congenital Ichthyosis (ARCI) is a group of rare genetic skin diseases associated with a total of 12 genes, the most recently identified being SDRC7 and SULT2B, with only a very few reported families. We report three ARCI patients born from non-consanguineous unrelated parents of French origin, who carried four previously unreported mutations in SDR9C7. All patients showed a mild ichthyosis with generalized scaly skin and mild palmoplantar keratoderma. None had alopecia or significant hypohidrosis. Only patient 1 (P1) was born as a collodion baby, had an ectropion of moderate severity and reported a skin improvement during her life. Past medical history revealed a growth delay for P2 and P3 and only P2 had a sparing of the face. By next generation sequencing, we identified the previously unreported homozygous mutation c.704G>A (p.Gly235Glu) in P1. P2 was heterozygous compound for two missense mutations: c.551A>G (p.Asp184Gly) and c.563G>A (p.Arg188His), this latter mutation was previously unreported and impacted the same codon than the known mutation c.562C>T (p.Arg188Cys) suspected to affect the splicing. P3 was heterozygous compound for 2 previously unreported mutations: the nonsense c.309A>G (p.Trp103Ter) and the missense c.826C>T (p.Arg276Cys) mutations. Currently, 16 other families with ARCI associated with SDR9C7 mutations were recorded. Similarly to other ARCI causing genes, there is no strict genotype-phenotype correlation. The new cases and mutations we report here expand the knowledge on the molecular bases of ARCI and help to better define the patient’s characteristics and the prognosis of this form of ichthyosis.

Identification of mutations in SDR9C7 in three patients with autosomal recessive congenital ichthyosis