Compound heterozygous mutations with novel missense ABCA12 mutation in harlequin ichthyosis.

Harlequin ichthyosis (HI) is the most severe form of autosomal recessive congenital ichthyosis, presenting at birth with distinctive facial features and thick, plate-like scales over the entire body. The abnormal skin barrier predisposes the patient to multiple complications, including dehydration and sepsis. Mortality rates of babies with HI have been greatly reduced since the introduction of systemic retinoid therapy. Mutations in ABCA12 have been found to lead to HI. Most of these mutations are truncation or deletion mutations in the conserved region of the protein, leading to severe loss of ABCA12 function. We report a case of HI caused by a compound heterozygous mutation (a known single nucleotide deletion and a novel single nucleotide substitution) in the ABCA12 gene.