Several novel genetic defects, such as variants in STAT1, DOCK8 (Dedicator of cytokinesis 8), AIRE (Autoimmune regulator) [23,33], FOXP3 (Forkhead box protein 3) [23], CXCR4 (CXC chemokine receptor 4) [16], BACH2 (BTB and CNC homolog 2) [34], or STAT3 (Signal transducer and activator of transcription 3) [23,35] causing immune dysregulation syndromes presenting as CVID have also been identified. This evidence concerns the gene STAT3 and common variable immunodeficiency.