Nijmegen breakage syndrome Q82.8

Nijmegen breakage syndrome (NBS) is a rare autosomal recessive syndrome of chromosomal instability characterized mainly by microcephaly at birth, combined immunodeficiency and predisposition to malignancies.

Nijmegen-Breakage syndrome belongs together with

• Fanconi anemia (FA)
• Ataxia teleangiectatica (A-T)
• Nijmegen-Breakage-Syndrome (NBS)
• Bloom syndrome (BS)

To the chromosome inst ability syndromes (Chromosome instability syndromes; Taylor AMR et al. 2019). This is an etiologically heterogeneous group of disorders involving chromosomal instability. Each of the listed syndromes exhibits a distinct pattern of chromosomal damage, and the cells of these patients are hypersensitive to certain genotoxic drugs, suggesting that the underlying defect is likely to be different in each case. In addition, each syndrome has a predisposition to malignancy.

The syndrome occurs most frequently in Slavic populations (Chrzanowska KH et al. 2012).

The cause of this complex syndrome is a mutation of the nibrin gene (NBS1) on chromosome 8 section q21-24 (Kondratenko I et al. 2007). Furthermore, mutations in the RAD50 gene can be detected.

Delayed growth, microcephaly, mental developmental disorders, immunodeficiencies, increased incidence of malignancies such as leukaemias, lymphomas, etc. (Kondratenko I et al. 2007). Patients with Nijmegen breakage syndrome have a significantly increased sensitivity to ionizing radiation and cytostatic drugs due to the increased chromosomal fragility.

There is no specific therapy for patients with this syndrome, but hematopoietic stem cell transplantation may be an option for some patients. The prognosis is generally poor due to the extremely high rate of malignancy.

1. Chrzanowska KH et al (2012) Nijmegen breakage syndrome (NBS). Orphanet J Rare Dis 7:13.
2. Kondratenko I et al (2007) Nijmegen breakage syndrome. Adv Exp Med Biol 601:61-67.
3. Maciejczyk M et al (2017) Oxidative stress, mitochondrial abnormalities and antioxidant defense in Ataxia-telangiectasia, Bloom syndrome and Nijmegen breakage syndrome. Redox Biol 11:375-383.
4. Taylor AMR et al (2019) Chromosome instability syndromes. Nat Rev Dis Primers. 5:64.