ABCA12 and ichthyosis: The main cause for HI are truncating mutations in ABCA12 (ichthyosis, congenital, autosomal recessive 4B (harlequin), and MIM #242500), whereas missense mutations in ABCA12 usually lead to milder phenotypes such as CIE or LI (ichthyosis, congenital, autosomal recessive 4A, and MIM #601277) [8,12].