Familial Hemophagocytic Lymphohistiocytosis Presenting as Hydrops Fetalis

Hemophagocytic lymphohistiocytosis (HLH) is caused by the prolonged and excessive activation of T-cells andmacrophages.1 HLH encompasses several entities; that is, primary familial HLH (FHL), which has an estimated incidence of 1 in 50,000 births, and a secondary form of HLH associated with infection, malig-nancies, and rheumatological disorders.2 FHL is a rare autosomal recessive disorder inwhich four different gene defects havebee