RALD also shares many features with ALPS, including lymphadenopathy, massive splenomegaly, increased circulating B cells, hypergammaglobulinemia, and autoimmune cytopenia, but germline or somatic mutations in FAS, FASL, or CASP10 characteristic for ALPS are absent in RALD. Here, CASP10 is linked to autoimmune lymphoproliferative syndrome.