TGM1 mutations are the predominant and most convincing causes of autosomal recessive congenital ichthyosis (ARCI; OMIM: 190195, 242100, 242300), a rare, nonsyndromic and heterogeneous disorder of cornification, having three distinct clinical subtypes, including, lamellar ichthyosis (LI; OMIM: 242300), harlequin ichthyosis (HI; OMIM: 242500) and congenital ichthyosiform erythroderma (CIE; OMIM: 242100) [26]. Here, TGM1 is linked to Harlequin ichthyosis.