Harlequin-type ichthyosis (also known as "Harlequin baby") or ichthyosis congenita, or Ichthyosis fetalis, a skin disease, is the most severe form of congenital ichthyosis, characterized by a thickening of the keratin layer in fetalhuman skin. In sufferers of the disease, the skin contains massive, diamond-shaped scales, and tends to have a reddish color. In addition, the eyes, ears, penis, and the appendages may be abnormally contracted. The scaly keratin greatly limits the child's movement. Because of resultant cracked skin in locations where normal skin would fold, it is easily pregnable by bacteria and other contaminants, resulting in serious risk of fatal infection It is associated with a mutat.ion in the gene for the protein ABCA12.