Harlequin-type ichthyosis, , a skin disease, is the most severe form of congenital ichthyosis, characterized by a thickening of the keratin layer in fetal human 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, mouth, and other appendages may be abnormally contracted. The scaly keratin greatly limits the child's movement. Because the skin is cracked where normal skin would fold, it is easily pregnable by bacteria and other contaminants, resulting in serious risk of fatal infection.
This disease is almost always fatal due to complications of the disease such as infection and trouble breathing. http://en.wikipedia.org/wiki/Harlequin_type_ichthyosis
The oldest person alive with it is a 24 year old female who I can't seen to find really any information on other than this news article: http://www.birminghampost.net/news/west-midlands-health-news/2008/05/09/nelly-is-a-real-diamond-girl-65233-20886612/
I'd post pictures but...They give me nightmares. Trust me...They are pretty gruesome as hell. Google at your own risk.