PRF1 and hemophagocytic syndrome: In this work, in addition to the somatic FAS mutation causing ALPS-sFAS detected in P1, a germline variant caller plugin revealed two heterozygous mutations in PRF1 and UNC13D genes predicted as possibly pathogenic, but not sufficient to cause hemophagocytic lymphohistiocytosis (41, 42) due to the autosomal recessive form of the disease.