CTLA4 gene haploinsufficiency with autoimmune infiltration (CHAI) leads to broad clinical manifestations such as hypogammaglobulinemia, enteropathy, recurrent infections, lymphocytic infiltration, and multiple autoimmune clinical features, very similar to characteristics of LRBA deficiency [5, 35–37]. Here, CTLA4 is linked to autoimmune lymphoproliferative syndrome due to CTLA4 haploinsufficiency.