Analysis of germline variation at the FMR1 CGG repeat shows variation in the normal-premutated borderline range
Analysis of germline variation at the FMR1 CGG repeat shows variation in the normal-premutated borderline range
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DOI：
10.1093/hmg/5.6.821
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发表时间：
1996-06-01
影响因子：
3.5
通讯作者：
Serre, JL
中科院分区：
文献类型：
--
作者：
Mornet, E;Chateau, C;Serre, JL
为了表征CGG重复不稳定性在脆性X综合征基因座（FMR 1基因）的动态，我们已经使用小池PCR来估计两个正常男性的生殖细胞（精子）和体细胞组织（白细胞）内的突变率，一个携带最常见的29 CGG重复等位基因，另一个携带55个重复的边界正常预突变等位基因。在精子和血液中发现55个重复的等位基因的重复的大收缩和适度的扩展，而在精子和血液中几乎没有发现与29个重复的等位基因的变异。与精子相比，体血DNA表现出较少的扩张和收缩。收缩比扩张更频繁，并且所有的扩张都在+4到+10的重复范围内发现，而大多数收缩都在-10到-30的范围内发现，这表明收缩的子集是由不同的机制引起的。这些结果还表明，CGG重复的动力学可能部分是由于高正常或premutated范围内的种系不稳定性。
In order to characterize the dynamics of CGG repeat instability at the fragile X syndrome locus (FMR1 gene), we have used small pool PCR to estimate the mutation rate within germline (sperm) and somatic tissue (leukocytes) of two normal males, one carrying the most common 29 CGG repeats allele, the other carrying a borderline normal-premutated allele of 55 repeats. Large contractions and moderate expansions of the repeat were found in sperm and blood for the 55 repeat allele while almost no variation was found in sperm or blood with the 29 repeat allele. Somatic blood DNA exhibited fewer expansions and contractions than sperm. Contractions were more frequent than expansions, and all the expansions were found in the +4 to +10 repeats range, while most of the contractions were found in the -10 to -30 range, suggesting that a subset of contractions results from a distinct mechanism. These results also suggest that the dynamics of the CGG repeat could be partly due to germline instability within the high normal or premutated ranges.