Screening of Nijmegen breakage syndrome 1 mutations in four unrelated families by polymerase chain reaction using sequence-specific primers.
Nijmegen breakage syndrome (NBS) is an autosomal recessive disorder characterized by a marked predisposition to lymphoreticular malignancies. The rarity of the disease and the presence, in several cases, of a mild clinical phenotype make diagnosis difficult. The underlying gene, NBS1, consists of 16 exons and encodes nibrin, a member of the hMRE11/hRAD50/hNBS1 protein complex. In addition to the "Slavic mutation," 657del5, identified in more than 100 patients with NBS, 9 other mutations have been found in families of different ethnic origin. We have developed a polymerase chain reaction (PCR) method to rapidly detect the private mutations, 742insGG and 835del4, in exon 7 and the 900del25 mutation in exon 8 of the NBS1 gene. In particular, we designed NBS1-specific primers for wild-type and mutated alleles, and optimized a specific PCR protocol for each mutation. We used this method to analyze 4 unrelated NBS families, 3 from Italy and 1 from Morocco. We believe it could be a useful tool for: (1) confirming the NBS diagnosis in the presence of clinical signs of the disease; (2) identifying NBS heterozygotes and performing prenatal diagnosis in families with affected members; and (3) screening selected populations in which the frequency of NBS might be higher because of a founder effect.
Di Masi
Alessandra
A
Department of Biology, University Roma Tre, Rome, Italy. dimasi@uniroma3.it
Antoccia
Antonio
A
Spadoni
Emanuela
E
Varon-Mateeva
Raymonda
R
Maraschio
Paola
P
Tanzarella
Caterina
C
D000483:Alleles; D018797:Cell Cycle Proteins / Q000235:genetics*; D025063:Chromosome Disorders / Q000175:diagnosis / Q000453:epidemiology / Q000235:genetics*; D004252:DNA Mutational Analysis / Q000379:methods; D005091:Exons / Q000235:genetics*; D005190:Family; D005260:Female; D005787:Gene Frequency / Q000235:genetics; D005808:Genes, Recessive; D006579:Heterozygote; D006801:Humans; D007558:Italy; D008297:Male; D008403:Mass Screening / Q000379:methods; D009154:Mutation; D049932:Nijmegen Breakage Syndrome / Q000175:diagnosis / Q000453:epidemiology / Q000235:genetics*; D009687:Nuclear Proteins / Q000235:genetics*; D010375:Pedigree; D016133:Polymerase Chain Reaction / Q000379:methods; D011296:Prenatal Diagnosis / Q000379:methods; D012680:Sensitivity and Specificity
D018797:Cell Cycle Proteins; C112156:NBN protein, human; D009687:Nuclear Proteins