BLK and common variable immunodeficiency: Variants in additional genes (not listed as “CVID genes” in OMIM), including BLK, CD27, CD70, CTLA4, IL21R, PIK3CD, PIK3R1, PLCG2, PRKCD, RAC2, TNFSF12 and VAV1 have also been associated with CVID (4, 8–10).