Górski Bohdan, Debniak Tadeusz, Jakubowska Anna, Cybulski Cezary, Huzarski Tomasz, Byrski Tomasz, Złowocka Elzbieta, Lubiński Jan
Department of Genetics and Pathology, Pomeranian Medical University, ul. Połabska 4, Szczecin 70-115, Poland.
J Appl Genet. 2003;44(3):419-23.
Founder mutations can account for a large proportion of BRCA1/BRCA2 gene abnormalities in a given population. However there is still a need to study the entire gene in many families, even in countries where founder mutations have been identified. It is possible to decrease the number of cases which are studied by complex and expensive sequencing/Southern blot analyses of BRCA1/BRCA2 genes by exclusion of common BRCA1/BRCA2 alleles in a given family by using polymorphic dinucleotide markers. The goal of o ur study was to assess the effectiveness of this method in exclusion of BRCA1/BRCA2 constitutional mutations. In each family, blood samples for genetic analyses were taken from two affected relatives from the same generation. Six polymorphic microsatellite markers linked to BRCA1/BRCA2 genes were analysed. Results obtained with these markers were verified by applying BRCA1 testing for the most common founder mutations in Poland and using exon by exon" sequencing of coding fragments of the BRCA2 gene. Polymorphic markers useful in BRCA1/BRCA2 analyses included only 3 of 6 examined - D17S855, D13S260 and D13S267. Occurrence of commoalleles of BRCA1 was excluded in 3 families and BRCA2 in 5 out of 30 families. Results obtained by testing for BRCA1 Polish founder mutations and BRCA2 sequencing were in agreement with BRCA1 findings based on polymorphic markers. The only exception was family 994 with BRCA1 exon 5 300T/G mutation, in which BRCA1 mutation carrier was excluded by using D17S855. Among 14 families without BRCA1 Polish founder mutations in this gene were excluded in 2 families and BRCA2 mutation was excluded in one family.
在特定人群中，奠基者突变可占BRCA1/BRCA2基因异常的很大比例。然而，即使在已发现奠基者突变的国家，许多家族仍有必要对整个基因进行研究。通过使用多态性二核苷酸标记物排除特定家族中常见的BRCA1/BRCA2等位基因，有可能减少通过复杂且昂贵的BRCA1/BRCA2基因测序/ Southern印迹分析所研究的病例数量。我们研究的目的是评估该方法在排除BRCA1/BRCA2结构突变方面的有效性。在每个家族中，从同一代的两名患病亲属采集用于基因分析的血样。分析了与BRCA1/BRCA2基因连锁的六个多态性微卫星标记。通过对波兰最常见的奠基者突变进行BRCA1检测以及对BRCA2基因编码片段进行逐外显子测序，验证了这些标记所获得的结果。在BRCA1/BRCA2分析中有用的多态性标记仅包括所检测的6个标记中的3个——D17S855、D13S260和D13S267。在3个家族中排除了BRCA1常见等位基因的存在，在30个家族中的5个家族中排除了BRCA2常见等位基因的存在。通过检测波兰BRCA1奠基者突变和BRCA2测序所获得的结果与基于多态性标记的BRCA1结果一致。唯一的例外是家族994，其具有BRCA1外显子5 300T/G突变，在该家族中通过使用D17S855排除了BRCA1突变携带者。在这14个没有波兰BRCA1奠基者突变的家族中，有2个家族排除了该基因的突变，1个家族排除了BRCA2突变。
