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Nijmegen breakage syndrome (NBS)

Nijmegen breakage syndrome (NBS) is a rare autosomal recessive disorder characterized by chromosomal instability, radiation sensitivity, microcephaly, growth retardation, immunodeficiency and predisposition to cancer, particularly to lymphoid malignancies.

The Nijmegen breakage syndrome and the phenotypically indistinguishable Berlin breakage syndrome are autosomal recessive chromosomal instability syndromes characterized by microcephaly, growth retardation, immunodeficiency, and predisposition to cancer. Ataxia-telangiectasia variant-1 is the designation applied to the Nijmegen breakage syndrome and AT variant-2 is the designation for the Berlin breakage syndrome, which differ only in complementation studies. Cells from NBS/BBS patients are hypersensitive to ionizing radiation with cytogenetic features indistinguishable from those of ataxia-telangiectasia (AT; 208900), but NBS/BBS patients have a distinct clinical phenotype.
The clinical features of LIG4 syndrome (606593), caused by mutation in the LIG4 gene (601837), resemble those of NBS.

NBS-1, the gene defective in NBS, is located on chromosome 8q21. The gene product, NIBRIN, is a protein, which is member of the hMre11/hRad50 protein complex. NBS is involved in DNA double strand break repair.

OTHER NAME(S): ATAXIA-TELANGIECTASIA VARIANT V1
MICROCEPHALY WITH NORMAL INTELLIGENCE, IMMUNODEFICIENCY, AND LYMPHORETICULAR MALIGNANCIES
SEEMANOVA SYNDROME II
NONSYNDROMAL MICROCEPHALY, AUTOSOMAL RECESSIVE, WITH NORMAL INTELLIGENCE
IMMUNODEFICIENCY, MICROCEPHALY, AND CHROMOSOMAL INSTABILITY
BERLIN BREAKAGE SYNDROME
ATAXIA-TELANGIECTASIA VARIANT V2

ABREVIATION(S):
NBS
AT-V1
BBS
AT-V2

TYPE: microcephaly, risk of malignant disease, chromosomal instability, sensitivity to radiation, growth retardation, immunodeficiency

Related patway(s): homologous recombination (HR)

DNAtraffic protein(s) related to disease: NBN (NBS1)

OMIM: 251260

Last modification date: Aug. 17, 2011