A variety of primary immunodeficiencies and congenital BM failure syndromes (predominantly with DNA repair impairment), including Nijmegen breakage syndrome, Ligase 4, Cernunnos, Rad50 deficiencies, Fanconi anemia, and some others, combine the symptoms of microcephaly and cytopenia [22, 23]. The gene discussed is RAD50; the disease is Nijmegen breakage syndrome.