Intronic mutations outside of Alu-repeat-rich domains of the LDL receptor gene are a cause of familial hypercholesterolemia
Intronic mutations outside of Alu-repeat-rich domains of the LDL receptor gene are a cause of familial hypercholesterolemia
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DOI：
10.1007/s00439-002-0813-4
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发表时间：
2002-12-01
期刊：
影响因子：
5.3
通讯作者：
Benlian, P
中科院分区：
文献类型：
--
作者：
Amsellem, S;Briffaut, D;Benlian, P
家族性高胆固醇血症（FH）。一种常见的单基因疾病，并发早发心血管疾病，其特征在于低密度脂蛋白受体（LDLR）基因座的高等位基因异质性。尽管进行了十多年的基因检测，但由于缺乏可用的基因组序列，有关内含子致病突变的知识仍然有限。基于从生物信息学分析的发现，Alu重复代表85%的LDLR内含子序列外的外显子-内含子连接，我们设计了一种策略，以提高探索基因组区域的外显子附近的110 FH受试者从混合人口。在第一组42例阴性突变携带者中，如先前通过先前的筛选策略（变性梯度凝胶电泳，DNA测序与先前的引物重叠剪接位点，Southern印迹）所确定的，约一半（n=22）被发现是至少一个杂合突变的携带者。在第二组68名新招募的患者中，27%的突变携带者（n=37）有剪接调节突变。总的来说，在鉴定的54个突变中，13个是内含子。18个是新的，其中近一半是内含子。根据神经网络计算的估计，两个新的内含子突变（多聚嘧啶段内的IVS 8 - 10 G-->A和供体位点下游的IVS 7 + 10 G-->A）可能产生潜在的异常剪接位点，与外显子-内含子连接处也鉴定出的31个常见单核苷酸变异相反。这一新的策略检测最有可能致病的LDLR突变以外的基因组区域丰富的内含子突变可能有更大的影响比以前报道的FH的分子基础。
Familial hypercholesterolemia (FH). a frequent monogenic condition complicated by premature cardiovascular disease, is characterized by high allelic heterogeneity at the low-density lipoprotein receptor (LDLR) locus. Despite more than a decade of genetic testing, knowledge about intronic disease-causing mutations has remained limited because of lack of available genomic sequences. Based on the finding from bioinformatic analysis that Alu repeats represent 85% of LDLR intronic sequences outside exon-intron junctions, we designed a strategy to improve the exploration of genomic regions in the vicinity of exons in 110 FH subjects from an admixed population. In the first group of 42 patients of negative mutation carriers, as previously established by former screening strategies (denaturing gradient get electrophoresis, DNA sequencing with former primers overlapping splice-sites, Southern Blotting), about half (n=22) were found to be carriers of at least one heterozygous mutation. Among a second group of 68 newly recruited patients, 27% of mutation carriers (n=37) had a splicing regulatory mutation. Overall, out of the 54 mutations identified, 13 were intronic. and 18 were novel, out of which nearly half were intronic. Two novel intronic mutations (IVS8-10G-->A within the polypyrimidine tract and IVS7+ 10G-->A downstream of donor site) might create potential aberrant splice sites according to neural-network computed estimation, contrary to 31 common single nucleotide variations also identified at exon-intron junctions. This new strategy of detecting the most likely disease-causing LDLR mutations outside of Alu-rich genomic regions reveals that intronic mutations may have a greater impact than previously reported on the molecular basis of FH.