TNFRSF13B and selective IgA deficiency disease: Whole-exome sequencing identified a pathogenic heterozygous frameshift mutation in the TNFRSF13B gene (c.105del, p. Glu36LysfsTer48; MAF: 0.0000544), maternally inherited, confirming a molecular diagnosis of common variable immunodeficiency type 2 with associated IgA deficiency.