Nijmegen breakage syndrome

Nijmegen breakage syndrome (NBS) is a rare autosomal recessive syndrome of chromosomal instability. 

The cause is  considered a founder mutation in the NBS1 gene (c.657_661del5) on chromosome 8q21. It is most common in West Slavic populations. The role of NBS1 is to arrest the cell cycle in the S phase when there are errors in the cell DNA; and to interact with FANCD2 that can activate the BRCA1/BRCA2 pathway of DNA repair. As a result of a NBS1 defect, there is a higher frequency of malignancies 1

  • microcephaly present at birth and
  • progressive with age, 
  • dysmorphic facial features, 
  • mild growth retardation
  • mild-to-moderate intellectual disability
  • in females hypergonadotropic hypogonadism

Patients with NBS carry hypersensitivity to x-radiation and gamma radiation, therefore CT is a relative contraindication.

Only small descriptive series exist on the MR features in NBS patient 2,3

Features present in all patients were:

  • microcephaly
  • decreased size of frontal lobes and narrow frontal horns of  the lateral ventricles 
  • sinusitis as a result of primary immunodeficiency 

Features present in some patients were:

Features in a few patients were:

  • callosal hypoplasia

There is no specific treatment for this syndrome. Haematopoietic  stem cell transplantation can be considered. The prognosis is poor due to the high frequecy of malignancies.

The condition was first described in the Dutch city of Nijmegen (Dutch pronunciation: [ˈnɛi̯.ˌmeː.ɣə(n)]).

The alternative name for the condition, "Seemanova syndrome", is named after Eva Seemanova, a Czech geneticist, publication in 1985 4.

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Article information

rID: 24738
Section: Syndromes
Synonyms or Alternate Spellings:
  • Berlin breakage syndrome
  • Seemanova syndrome

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