Barth syndrome is a rare disease caused by a sex-linked mutation. It was discovered by Dr. Peter Barth in the Netherlands. The symptoms are weakness of the striated muscles, both skeletal and cardiac; weakness of the immune system; and failure to thrive. Barth boys often die before they are five years old, but if they survive past that age, they are not likely to die from it.

External link: http://www.barthsyndrome.org/