Heterologous IKZF mutation in B cell deficiency and autoimmunity [25], heterologous TNFAIP3 mutation in autoinflammation and immunodeficiency [26], heterologous IKBKB variant in common variable immunodeficiency [27], and homozygous TNFSF13 (APRIL) deficiency in plasmacyte defect [28] were reported in the past 5 years. This evidence concerns the gene TNFSF13 and immune system disorder.