Non-bullous congentital ichthyosiform erythroderma associated with homozygosity for a novel missense mutation in an ATP binding domain of ABCA12.

A Mutations in the gene encoding the ABCA12 protein are associated with different subtypes of autosomal recessive congenital ichthyosis (ARCI), including Harlequin ichthyosis (HI), lamellar ichthyosis (LI) and non-bullous congenital ichthyosiform erythroderma (NCIE). Disruption of ABCA12 lead to perturbed lipid transport in lamellar granules and a defective intercellular lipid layer of the stratum corneum. We have identified a large consanguineous Pakistani family affected by NCIE. Autozygosity mapping showed that affected individuals are homozygous for the ABCA12 gene region. Subsequent mutation screening revealed a homozygous c.4676G>T transition in all five affected family members. The mutation results in a novel p.G1559V substitution within the first nucleotide binding domain of ABCA12. The combined results support that an ABCA12 missense mutation, despite its location in a functional domain, may be associated with a mild ichthyosis phenotype. Furthermore, our findings increase the mutational spectrum in ABCA12 associated with ARCI of diagnostic and prognostic importance.