Five patients had specific immunoglobulin deficiencies (IgG, IgA, or both) [20, 25–27]; 4 patients had otherwise unspecified hypogammaglobulinemia [25, 26]; 2 patients had antibody deficiency with syndromic features [26]; and 1 patient had activated PI3K delta syndrome (APDS) [26]. Here, CD79A is linked to Down syndrome.