Meta-Biol

• Pathways

ATP-binding cassette sub-family A member 12 (ABCA12) is thought to function as an epidermal keratinocyte lipid transporter. Lipids such as glucosylceramides and gangliosides form extracellular lipid layers in the stratum corneum of the epidermis, essential for skin barrier function. Defects in ABCA12 results in the loss of the skin lipid barrier, leading to autosomal recessive congenital ichthyosis 4B (ARCI4B; MIM:242500, aka harlequin ichthyosis, HI). ARCI4B shows the most severe phenotype of the congenital ichthyoses, with newborns having a thick covering of armour-like scales. Mutations causing ARCI4B include V2442Sfs*22, K1671Ifs*4, D2363N, G1179R and R287* (Kelsell et al. 2005, Thomas et al. 2006, Castiglia et al. 2009).