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]. This evidence concerns the gene RAD50 and microcephaly.