PRF1 and hemophagocytic syndrome: Primary HLH, or familial HLH (FHL), results from genetic mutations affecting cytotoxic lymphocyte function.<h4>Case report</h4>We present a case of FHL Type 2 (FHL2) caused by compound heterozygous variants in the PRF1 gene, including one novel missense variant of p.Ala21Val (A21V).