http://www.histio.org/site/c.kiKTL4PQLvF/b.1810505/k.F16D/Disease_Information.htm
Histiocytosis Association of America
This site provides basic information about histiocytosis, a very rare disorder which affects an estimated 1 in 200,000 children born each year in the United States. This illness is so rare, there is little research into its cause and treatment, and it is often referred to as an "orphan disease," meaning it strikes too few people to generate government - supported research.