@article {6555, title = {Association of levels of fasting glucose and insulin with rare variants at the chromosome 11p11.2-MADD locus: Cohorts for Heart and Aging Research in Genomic Epidemiology (CHARGE) Consortium Targeted Sequencing Study.}, journal = {Circ Cardiovasc Genet}, volume = {7}, year = {2014}, month = {2014 Jun}, pages = {374-382}, abstract = {

BACKGROUND: Common variation at the 11p11.2 locus, encompassing MADD, ACP2, NR1H3, MYBPC3, and SPI1, has been associated in genome-wide association studies with fasting glucose and insulin (FI). In the Cohorts for Heart and Aging Research in Genomic Epidemiology Targeted Sequencing Study, we sequenced 5 gene regions at 11p11.2 to identify rare, potentially functional variants influencing fasting glucose or FI levels.

METHODS AND RESULTS: Sequencing (mean depth, 38{\texttimes}) across 16.1 kb in 3566 individuals without diabetes mellitus identified 653 variants, 79.9\% of which were rare (minor allele frequency <1\%) and novel. We analyzed rare variants in 5 gene regions with FI or fasting glucose using the sequence kernel association test. At NR1H3, 53 rare variants were jointly associated with FI (P=2.73{\texttimes}10(-3)); of these, 7 were predicted to have regulatory function and showed association with FI (P=1.28{\texttimes}10(-3)). Conditioning on 2 previously associated variants at MADD (rs7944584, rs10838687) did not attenuate this association, suggesting that there are >2 independent signals at 11p11.2. One predicted regulatory variant, chr11:47227430 (hg18; minor allele frequency=0.00068), contributed 20.6\% to the overall sequence kernel association test score at NR1H3, lies in intron 2 of NR1H3, and is a predicted binding site for forkhead box A1 (FOXA1), a transcription factor associated with insulin regulation. In human HepG2 hepatoma cells, the rare chr11:47227430 A allele disrupted FOXA1 binding and reduced FOXA1-dependent transcriptional activity.

CONCLUSIONS: Sequencing at 11p11.2-NR1H3 identified rare variation associated with FI. One variant, chr11:47227430, seems to be functional, with the rare A allele reducing transcription factor FOXA1 binding and FOXA1-dependent transcriptional activity.

}, keywords = {Aged, Aged, 80 and over, Aging, Blood Glucose, Chromosomes, Human, Pair 11, Cohort Studies, Death Domain Receptor Signaling Adaptor Proteins, Diabetes Mellitus, Type 2, Fasting, Female, Gene Frequency, Genetic Variation, Genome-Wide Association Study, Genomics, Guanine Nucleotide Exchange Factors, Heart Diseases, Humans, Insulin, Male, Middle Aged, Polymorphism, Single Nucleotide, Sequence Analysis, DNA}, issn = {1942-3268}, doi = {10.1161/CIRCGENETICS.113.000169}, author = {Cornes, Belinda K and Brody, Jennifer A and Nikpoor, Naghmeh and Morrison, Alanna C and Chu, Huan and Ahn, Byung Soo and Wang, Shuai and Dauriz, Marco and Barzilay, Joshua I and Dupuis, Jos{\'e}e and Florez, Jose C and Coresh, Josef and Gibbs, Richard A and Kao, W H Linda and Liu, Ching-Ti and McKnight, Barbara and Muzny, Donna and Pankow, James S and Reid, Jeffrey G and White, Charles C and Johnson, Andrew D and Wong, Tien Y and Psaty, Bruce M and Boerwinkle, Eric and Rotter, Jerome I and Siscovick, David S and Sladek, Robert and Meigs, James B} } @article {7005, title = {Association of the IGF1 gene with fasting insulin levels.}, journal = {Eur J Hum Genet}, volume = {24}, year = {2016}, month = {2016 Aug}, pages = {1337-43}, abstract = {

Insulin-like growth factor 1 (IGF-I) has been associated with insulin resistance. Genome-wide association studies (GWASs) of fasting insulin (FI) identified single-nucleotide variants (SNVs) near the IGF1 gene, raising two hypotheses: (1) these associations are mediated by IGF-I levels and (2) these noncoding variants either tag other functional variants in the region or are directly functional. In our study, analyses including 5141 individuals from population-based cohorts suggest that FI associations near IGF1 are not mediated by IGF-I. Analyses of targeted sequencing data in 3539 individuals reveal a large number of novel rare variants at the IGF1 locus and show a FI association with a subset of rare nonsynonymous variants (PSKAT=5.7 {\texttimes} 10(-4)). Conditional analyses suggest that this association is partly explained by the GWAS signal and the presence of a residual independent rare variant effect (Pconditional=0.019). Annotation using ENCODE data suggests that the GWAS variants may have a direct functional role in insulin biology. In conclusion, our study provides insight into variation present at the IGF1 locus and into the genetic architecture underlying FI levels, suggesting that FI associations of SNVs near IGF1 are not mediated by IGF-I and suggesting a role for both rare nonsynonymous and common functional variants in insulin biology.

}, issn = {1476-5438}, doi = {10.1038/ejhg.2016.4}, author = {Willems, Sara M and Cornes, Belinda K and Brody, Jennifer A and Morrison, Alanna C and Lipovich, Leonard and Dauriz, Marco and Chen, Yuning and Liu, Ching-Ti and Rybin, Denis V and Gibbs, Richard A and Muzny, Donna and Pankow, James S and Psaty, Bruce M and Boerwinkle, Eric and Rotter, Jerome I and Siscovick, David S and Vasan, Ramachandran S and Kaplan, Robert C and Isaacs, Aaron and Dupuis, Jos{\'e}e and van Duijn, Cornelia M and Meigs, James B} }