title: [Heterozygous carriers of Slavic mutation 657del5 of NBN gene in patients with colorectal cancer].
abstract: BACKGROUND
  Nijmegen breakage syndrome (NBS) is one of the chromosomal instability syndromes due to DNA repair disorder. The syndrome is autosomal recessive determined, in homozygotes is characterized by many disorders including high predisposition to lymphoreticular malignancy in childhood and adolescence.
  
  
  METHODS
  Laboratory findings represent low level of immunoglobulins, B and T lymphocytes, increased sensitivity to the mutagens, especially hyperradiosensitivity and increased chromosomal instability. Heterozygotes show also elevated radiosensitivity and have an increased cancer risk in adult age. There is no predilection of the malignancy. Colorectal cancer was found often among the relatives of patients with NBS. Majority of the NBS patients are of the Central and Eastern European origin and carry the common founder mutation 657del5 in the NBN gene. The formation of second malignancy both in homozygotes and heterozygotes can be prevented by excluding any radiation. The aim of study is estimation of frequency of 657del5 heterozygotes among patients with colorectal cancer.
  
  
  CONCLUSIONS
  Within a group of 161 patients with colorectal cancer 5 heterozygotes with 657del5 mutation were registered, e.g. 5-times higher incidence than expected. The elemental prevention in patients with proved positivity of Slavic mutation in NBN gene is to exclude any radiation.
authors.affiliation: Univerzita Karlova v Praze, 2. lékarská fakulta a FN Motol, Ustav biologie a lékarské genetiky. eva.seemanova@Ifmotol.cuni.cz
authors.forename: Eva
authors.initials: E
authors.lastname: Seemanová
authors.forename: Jirí
authors.initials: J
authors.lastname: Hoch
authors.forename: Pavel
authors.initials: P
authors.lastname: Seeman
mesh_terms: D000328:Adult; D000368:Aged; D018797:Cell Cycle Proteins / Q000235:genetics*; D015179:Colorectal Neoplasms / Q000209:etiology / Q000235:genetics*; D005260:Female; D006579:Heterozygote; D006801:Humans; D008297:Male; D008875:Middle Aged; D009154:Mutation; D049932:Nijmegen Breakage Syndrome / Q000150:complications / Q000235:genetics; D009687:Nuclear Proteins / Q000235:genetics*; D018154:Slovakia
chemical_list: D018797:Cell Cycle Proteins; C112156:NBN protein, human; D009687:Nuclear Proteins