In ALPS-FAS, the impaired apoptosis and the consequent expansion of specific subsets of lymphocytes (4) (i.e., total CD3+ T-cells, CD3+CD8+ T-cells, CD3+TCRαβ+CD4−CD8− double negative T-cells, CD5+CD20+ B-cells), including self-antigen reactive subpopulations, results in specific clinical manifestations and laboratory abnormalities such as lymphadenopathy, hepatomegaly, splenomegaly, autoimmune hemolytic anemia, thrombocytopenia, and neutropenia (5, 6). This evidence concerns the gene FAS and Splenomegaly.