A Novel Compound Heterozygous Stxbp2 Mutation in a Case with Familial Hemophagocytic Lymphohistiocytosis

Familial or primary hemophagocytic lymphohistiocytosis (FHLH) is a rare genetic disease with autosomal recessive inheritance. FHLH is usually diagnosed during infancy and it is characterized by fever, hepatosplenomegaly, pancytopenia and less often involvement of the central nervous system. One of the diagnostic criteria is demonstrating a previously known mutation. Known gene mutations related to FHLH are perforin (PRF1; FHLH 2), UNC13D (FHLH 3), syntaxin 11 (STX11; FHLH 4), syntaxin-binding protein 2 (STXBP2; FHLH 5) and unknown gene mutations localized on chromosome 9q21.3-q22 (FHLH 1). The STXBP-2 (FHLH 5) mutation is a poor prognosis HLH type frequently seen in infants after gastroenteritis. We detected a novel compound heterozygous STXBP2 mutation in a six-month-old infant presenting with acute hepatitis and meeting the HLH diagnostic criteria and who developed reactivation with diarrhea and CNS involvement findings after the HLH 2004 treatment protocol was used.