An autistic male child with a history of recurrent lower respiratory tract and ear infections requiring tympanostomy tube placement, tonsillectomy, and adenoidectomy (Supplemental Table 1; supplemental material available online with this article; https://doi.org/10.1172/jci.insight.155481DS1) was diagnosed with mild hypogammaglobulinemia (IgG 584 mg/dL, IgA 85 mg/dL, IgM 54 mg/dL, IgE 12 kU/L) and treated with immunoglobulin replacement. The gene discussed is CD79A; the disease is ear infection.