As an example, whole exome sequencing of a six boys of four unrelated families with X-linked agammaglobulinemia and Mohr–Tranebjaerg syndrome revealed a large deletion in all patients, and in one case deletion included the genes TIMM8A, TAF7L, and DRP2. Of note, the cases suffered from neurological impairments and sensorineural deafness (19). This evidence concerns the gene DRP2 and isolated agammaglobulinemia.