Wagner T M, Hirtenlehner K, Shen P, Moeslinger R, Muhr D, Fleischmann E, Concin H, Doeller W, Haid A, Lang A H, Mayer P, Petru E, Ropp E, Langbauer G, Kubista E, Scheiner O, Underhill P, Mountain J, Stierer M, Zielinski C, Oefner P
Division of Senology, Ludwig Boltzmann Institute for Clinical Experimental Oncology, University of Vienna, 1090 Vienna, Austria.
Hum Mol Genet. 1999 Mar;8(3):413-23. doi: 10.1093/hmg/8.3.413.
The aim of this study was to evaluate the prevalence of simple sequence variation in the BRCA2 gene. To this end, 71 breast and breast-ovarian cancer (HBC/HBOC) families along with 95 control individuals from a wide range of ethnicities were analyzed by means of denaturing high-performance liquid chromatography (DHPLC) and direct sequence analysis. In the coding (10 257 bp) and non-coding (2799 bp) sequences of BRCA2, 82 sequence variants were identified. Three different, apparently disease-associated BRCA2 mutations were found in six HBC/HBOC families (8%): two splice site mutations in introns 5 and 21, and one frameshift mutation in exon 11. In the coding region, 53 simple sequence variants were found: 35 missense mutations, one 2 bp deletion (CT) resulting in a stop at codon 3364, one nonsense mutation with a stop at codon 3326, one deletion of a complete codon (AAA) resulting in the loss of leucine, and 15 silent mutations. In the non-coding region, 26 polymorphisms were detected. Of the 79 sequence variants that were not obviously disease-associated, eight were detected only in HBC/HBOC families. The remaining 71 variants were identified in both HBC/HBOC families and control individuals. Sixty three sequence variants (80%) were specific for a continent. Forty two percent (33 out of 79) of the sequence variants were detected exclusively in Africa, though only 13% of the 332 chromosomes screened were of African origin. Our data indicate that, in BRCA2, simple sequence variation is frequent [in the coding region 1 in 194 bp (straight theta = 2.2 x 10(-4)), and in the non-coding region 1 in 108 bp (straight theta = 4.4 x 10(-4)), respectively].
本研究的目的是评估BRCA2基因中简单序列变异的发生率。为此，采用变性高效液相色谱法（DHPLC）和直接测序分析法，对71个乳腺癌和乳腺-卵巢癌（HBC/HBOC）家系以及95名来自不同种族的对照个体进行了分析。在BRCA2基因的编码序列（10257 bp）和非编码序列（2799 bp）中，共鉴定出82个序列变异。在6个HBC/HBOC家系（8%）中发现了3种不同的、明显与疾病相关的BRCA2突变：内含子5和21中的2个剪接位点突变，以及外显子11中的1个移码突变。在编码区，发现了53个简单序列变异：35个错义突变、1个导致第3364位密码子处终止的2 bp缺失（CT）、1个在第3326位密码子处终止的无义突变、1个导致亮氨酸缺失的完整密码子（AAA）缺失，以及15个沉默突变。在非编码区，检测到26个多态性。在79个并非明显与疾病相关的序列变异中，有8个仅在HBC/HBOC家系中检测到。其余71个变异在HBC/HBOC家系和对照个体中均有鉴定。63个序列变异（80%）具有大陆特异性。42%（79个中的33个）的序列变异仅在非洲检测到，尽管所筛查的332条染色体中只有13%来自非洲。我们的数据表明，在BRCA2基因中，简单序列变异很常见[在编码区分别为每194 bp出现1个（直θ=2.2×10⁻⁴），在非编码区为每108 bp出现1个（直θ=4.4×10⁻⁴）]。
