Van Camp Jasmijn K, De Freitas Fenna, Zegers Doreen, Beckers Sigri, Verhulst Stijn L, Van Hoorenbeeck Kim, Massa Guy, Verrijken An, Desager Kristine N, Van Gaal Luc F, Van Hul Wim
Department of Medical Genetics, University of Antwerp, Universiteitsplein 1, 2610, Antwerp, Belgium.
Department of Paediatrics, Antwerp University Hospital, Wilrijkstraat 10, 2650, Antwerp, Belgium.
Endocrine. 2016 May;52(2):277-86. doi: 10.1007/s12020-015-0778-4. Epub 2015 Oct 26.
The aim of this study was to confirm the previously identified link between BAMBI and human obesity by means of a genetic and functional analysis. We performed both a mutation analysis, using high-resolution melting curve analysis, and a genetic association study, including 8 common tagSNPs in the BAMBI gene region. Three of the identified genetic variants (R151W, H201R, and C229R) were evaluated for their Wnt signaling enhancing capacity in a Wnt luciferase reporter assay. Mutation screening of the BAMBI coding region and exon-intron boundaries on our population of 677 obese children and adolescents and 529 lean control subjects resulted in the identification of 18 variants, 10 of which were not previously reported and 12 of which were exclusively found in obese individuals. The difference in variant frequency, not taking into account common polymorphisms, between obese (3.1 %) and lean (0.9 %) subjects was statistically significant (p = 0.004). Our Wnt luciferase assay, using WT and mutant BAMBI constructs, showed a significantly reduced activity for all of the investigated variants. Logistic and linear regression analysis on our Caucasian population of 1022 obese individuals and 606 lean controls, did not identify associations with obesity parameters (p values >0.05). We found several rare genetic variations, which represent the first naturally occurring missense variants of BAMBI in obese patients. Three variants (R151W, H201R, and C229R) were shown to reduce Wnt signaling enhancing capacity of BAMBI and we believe this result should encourage further study of this gene in other obese populations. In addition, we did not find evidence for the involvement of BAMBI common variation in human obesity in our population.
本研究的目的是通过基因和功能分析来证实先前确定的BAMBI与人类肥胖之间的联系。我们进行了突变分析（采用高分辨率熔解曲线分析）以及基因关联研究（包括BAMBI基因区域的8个常见标签单核苷酸多态性）。对鉴定出的3个基因变异（R151W、H201R和C229R），在Wnt荧光素酶报告基因检测中评估其增强Wnt信号传导的能力。在我们的677名肥胖儿童和青少年以及529名瘦对照受试者群体中，对BAMBI编码区和外显子 - 内含子边界进行突变筛查，结果鉴定出18个变异，其中10个是先前未报道的，12个是仅在肥胖个体中发现的。肥胖（3.1%）和瘦（0.9%）受试者之间变异频率的差异（不考虑常见多态性）具有统计学意义（p = 0.004）。我们使用野生型和突变型BAMBI构建体进行的Wnt荧光素酶检测显示，所有研究的变异体活性均显著降低。对我们1022名肥胖个体和606名瘦对照的白种人群体进行逻辑回归和线性回归分析，未发现与肥胖参数的关联（p值>0.05）。我们发现了几个罕见的基因变异，它们是肥胖患者中BAMBI首次自然发生的错义变异。三个变异体（R151W、H201R和C229R）显示出降低BAMBI增强Wnt信号传导的能力，我们认为这一结果应促使在其他肥胖人群中对该基因进行进一步研究。此外，在我们的群体中未发现BAMBI常见变异与人类肥胖有关的证据。
