Chromosome abnormalities in familial hemophagocytic lymphohistiocytosis

Familial hemophagocytic lymphohistiocytosis (FHLH) is an uncommon disorder characterized by multiorgan infiltration with phagocytic histiocytes/macrophages. It may be inherited as an autosomal recessive trait, but specific associated cytogenetic abnormalities have not been documented. The authors describe a 10-week-old white female without prior family history of FHLH, who fulfilled the histologic and clinical criteria for the diagnosis. In addition, cytogenetic abnormalities, including the presence of double minute chromosomes and occasional loss of chromosomes 7 and 12, were documented in unstimulated peripheral blood cells. These karyotypic findings are usually associated with dyserythropoietic and leukemic states, and have not been described previously in the context of FHLH. It may be useful to do chromosome analyses on unstimulated peripheral blood cultures from FHLH patients before treatment to examine the karyotype of proliferating cells, which may represent the infiltrative histiocytes seen in the disorder.