Letterer–Siwe disease

Letterer–Siwe disease is a genetic disorder considered to be a type of histiocytosis (a condition where histiocytes proliferate in the body). It is sometimes classified as a form of Langerhans cell histiocytosis, or as a form of histiocytosis X. It is most commonly seen in children less than two years old. The disorder is believed to be inherited in an autosomal recessive pattern