Nijmegen breakage syndrome is a rare genetic disease presenting at birth with microcephaly, dysmorphic facial features, becoming more noticeable with age, growth delay, and later-onset complications such as malignancies and infections. The disease is Nijmegen breakage syndrome (MONDO_0009623). Also known as: AT V1, Berlin breakage syndrome, NBS, NBs, Seemanova syndrome, Seemanova syndrome type 2, ataxia-telangiectasia, variant 1, immunodeficiency-microcephaly-chromosomal instability syndrome.