PIK3CD and common variable immunodeficiency: Genetic analyses of subjects with a CVID phenotype have identified recessively inherited traits with biallelic mutations in ICOS, CD19, CD20, CD21, CD81, PRKCD, and LRBA, and autosomal dominant traits with monoallelic mutations in PIK3CD, NFKB2, PIK3R1 (1), and, most recently, NFKB1 (3) and, as we have shown, IKZF1 (4).