TGM1 and Harlequin ichthyosis: To validate the expression of canonical granular markers in ICs, we performed immunofluorescence staining of Tgm1, an enzyme that performs protein cross-linking of structural proteins for cornified envelope formation, and Abca12, which plays a role in transporting lipids into lamellar bodies and is disrupted in harlequin ichthyosis (Akiyama, 2010; Thomas et al., 2006).