For instance, loss-of-function (LOF) in LG lipid transporter ATP binding cassette subfamily A member 12 (ABCA12) results in ARCI4B (harlequin ichthyosis, OMIM #2425500), while that in transglutaminase 1 (TGM1) impairs corneocyte lipid envelope formation [3] and causes ARCI1 (lamellar ichthyosis (LI), OMIM #242300) [5]. Here, ABCA12 is linked to Harlequin ichthyosis.