Novel STXBP2 Mutation Causing Familial Hemophagocytic Lymphohistiocytosis.

Familial Hemophagocytic Lymphohistiocytosis (FHL) is a rare autosomal recessive disorder. Diagnosis is established in presence of genetic mutation or positive family history in one of the siblings. Common genetic mutations associated with FHL are mutations in gene PRF-1 (also known as FHL 2), UNC13D (FHL 3) and STX11 (FHL 4). Recently mutation in STXBP2 encoding syntaxin binding protein 2 (Munc 18 -2) has been found to be associated with FHL type 5. Here we describe the first reported Indian patient with homozygous mutation in STX BP2 gene (c1697 G>A resulting in amino acid change p.G566D) causing FHL 5.