STAT3 and common variable immunodeficiency: More than one subject had mutations in heterozygous genes previously found in subjects with a CVID phenotype: IRF2BP2, CTLA4 and IKZF1 (in 6 subjects each), TCF3 (in 5 subjects), BACH2 (in 4 subjects), and in STAT3, and PIK3CD (3 subjects for each).