To date, in our collection of about 550 families presenting with ARCI we identified mutations in seven different genes, which can cause non-syndromic forms of ARCI: ABCA12, ALOXE3, ALOX12B, CYP4F22, ICHTHYIN, PNPLA1, and TGM1[1]–[6] in about 80% of the patients; the remaining 20% of patients are expected to carry mutations in other genes, which remain to be identified [7]. This evidence concerns the gene CYP4F22 and autosomal recessive congenital ichthyosis.