Haemophagocytic lymphohistiocytosis associated with constitutional inversion of chromosome 9.

Familial haemophagocytic lymphohistiocytosis (HLH) is considered an autosomal recessive disease, although the putative gene responsible for the disease has not yet been localized. Identification of the involved gene may elucidate the pathogenesis of the disease and is essential for prenatal testing in affected families. We present an infant with HLH and constitutional inversion 9 (p23q31) in cells from bone marrow, lymphocytes and fibroblasts. The parents had normal karyotypes. It may be speculated that one of the parents was a carrier of HLH and a de novo inversion occurred in chromosome 9 from the non-carrier parent. This would imply that the putative HLH-related gene is located at one of the two breakpoints on chromosome 9.