Most patients in the ATM (92.5%) and STAT3 (AD-LOF) (89.5%) groups had similar clinical diagnoses, however, patients with DNMT3B/ZBTB24 mutations were first diagnosed with hypogammaglobulinemia (13, 68.4%), immunoglobulin A deficiency (2, 10.5%), and agammaglobulinemia (1, 5.3%). The gene discussed is ATM; the disease is selective IgA deficiency disease.