FAS and autoimmune lymphoproliferative syndrome: In the present case report, we described the phenotype of a 9-year-old boy who carried compound heterozygous mutations (c.139G>T, p.G47C; c.305G>T, p.C102F) in PRF1 and a spontaneous mutation (c.776T>C, p.I259T) in the FAS, presenting with features of FHL and ALPS.