Harlequin ichthyosis (HI) is the most devastating form of congenital ichthyosis. The newborns with this disease show severe hyperkeratosis and scales with fissures over the whole body, pronounced ectropion, and impaired contraction of ears and limbs. HI is associated with truncations/deletions in ABCA12, an ATP-binding cassette (ABC) transporters with lipid transporter activity in keratinocytes.
