Genetic and functional identification of the likely causative variant for cholesterol gallstone disease at the ABCG5/8 lithogenic locus
Genetic and functional identification of the likely causative variant for cholesterol gallstone disease at the ABCG5/8 lithogenic locus
复制标题
ABCG5/8 成石位点胆固醇胆结石疾病可能致病变异的遗传和功能鉴定
DOI：
10.1002/hep.26009
复制
发表时间：
2013-06-01
期刊：
影响因子：
13.5
通讯作者：
Hampe, Jochen
中科院分区：
文献类型：
--
作者：
von Kampen, Oliver;Buch, Stephan;Hampe, Jochen
固醇基因座（ABCG5/ABCG8）与人类胆固醇结石病的易感性有关。在这些患者中，导致胆结石发病率增加的致病变异和分子机制尚未确定。遗传图谱利用了来自德国（2808例，2089例对照）、智利（680例，442例对照）、丹麦（366例，766例对照）、印度（247例，224例对照）和中国（280例，244例对照）的患者样本。利用焦磷酸测序法分析了22例人肝脏互补DNA （cDNA）样本的等位基因失衡。瞬时转染的HEK293细胞用于[3H]‐胆固醇输出测定、蛋白质表达分析和等位基因构建的定位。通过对德国和智利样本的精细定位，可以为该基因座定义一个~ 250 kB的疾病相关间隔。人类肝脏中ABCG5和ABCG8转录本缺乏等位基因不平衡或等位基因剪接，限制了对单核苷酸多态性的编码搜索。随后的突变检测和基因分型发现了两个与疾病相关的变异：ABCG5‐R50C （P = 4.94 × 10−9）和ABCG8‐D19H (P = 1.74 × 10−10)，存在高两两连锁不平衡（r2 = 0.95）。[3H]‐胆固醇输出分析显示，只有ABCG8‐19H变异的转运活性增加（3.2倍，P = 0.003），这在德国（P = 0.018）、智利（P = 0.030）和中国（P = 0.040）患者样本的嵌套逻辑回归模型中也更优越。结论：该变异为胆道胆固醇高分泌作为胆固醇胆结石形成机制提供了分子基础，从而在这种常见复杂疾病的“基因组后”和“基因组前”病理生理知识之间建立了联系。(肝脏病学2012)
The sterolin locus (ABCG5/ABCG8) confers susceptibility for cholesterol gallstone disease in humans. Both the responsible variant and the molecular mechanism causing an increased incidence of gallstones in these patients have as yet not been identified. Genetic mapping utilized patient samples from Germany (2,808 cases, 2,089 controls), Chile (680 cases, 442 controls), Denmark (366 cases, 766 controls), India (247 cases, 224 controls), and China (280 cases, 244 controls). Analysis of allelic imbalance in complementary DNA (cDNA) samples from human liver (n = 22) was performed using pyrosequencing. Transiently transfected HEK293 cells were used for [3H]‐cholesterol export assays, analysis of protein expression, and localization of allelic constructs. Through fine mapping in German and Chilean samples, an ∼250 kB disease‐associated interval could be defined for this locus. Lack of allelic imbalance or allelic splicing of the ABCG5 and ABCG8 transcripts in human liver limited the search to coding single nucleotide polymorphisms. Subsequent mutation detection and genotyping yielded two disease‐associated variants: ABCG5‐R50C (P = 4.94 × 10−9) and ABCG8‐D19H (P = 1.74 × 10−10) in high pairwise linkage disequilibrium (r2 = 0.95). [3H]‐cholesterol export assays of allelic constructs harboring these genetic candidate variants demonstrated increased transport activity (3.2‐fold, P = 0.003) only for the ABCG8‐19H variant, which was also superior in nested logistic regression models in German (P = 0.018), Chilean (P = 0.030), and Chinese (P = 0.040) patient samples. Conclusion: This variant thus provides a molecular basis for biliary cholesterol hypersecretion as the mechanism for cholesterol gallstone formation, thereby drawing a link between “postgenomic” and “pregenomic” pathophysiological knowledge about this common complex disorder. (HEPATOLOGY 2012)