According to the current European Society for Immunodeficiency (ESID) criteria, besides other humoral immunodeficiencies such as unclassified antibody deficiency, selective IgA/IgM deficiency, and isolated IgG subclass deficiency, common variable immunodeficiency disorder (CVID) is the most common symptomatic antibody deficiency, affecting approximately 20% of PID patients [2, 3]. The gene discussed is CD79A; the disease is agammaglobulinemia.