From the Frankfurt cohort, 35/66 (53%) patients, median 10 years, aged from 1 to 38 years, of whom 19 males and 16 females presented with IgA deficiency, 31 patients exhibited no deficient IgA, median age 15 years ranging from 2 to 39 years, 16 males and 15 females. The gene discussed is CD79A; the disease is selective IgA deficiency disease.