NBN and Nijmegen breakage syndrome: Mutations at the homozygous or compound heterozygous status within the NBN gene are responsible for the Nijmegen breakage syndrome (NBS; OMIM #251260) [36], [37], a rare genetic disorder characterized by an autosomic recessive inheritance, whose signs are, among others, microcephaly, humoral and cellular immunodeficiency, and radiosensitivity [3], [6], [38]–[40].