Common variable immunodeficiency (CVID) is one of the most prevalent PAD disorders, and defined as a marked decrease in serum immunoglobulin (Ig) G with a marked decrease in serum IgM and/or IgA, poor antibody responses to vaccination, and exclusion of secondary or other defined causes of hypogammaglobulinemia (1). The gene discussed is GAN; the disease is common variable immunodeficiency.