Replication of genome-wide association signals in UK samples reveals risk loci for type 2 diabetes
SCIENCE
Authors: Zeggini, Eleftheria; Weedon, Michael N.; Lindgren, Cecilia M.; Frayling, Timothy M.; Elliott, Katherine S.; Lango, Hana; Timpson, Nicholas J.; Perry, John R. B.; Rayner, Nigel W.; Freathy, Rachel M.; Barrett, Jeffrey C.; Shields, Beverley; Morris, Andrew P.; Ellard, Sian; Groves, Christopher J.; Harries, Lorna W.; Marchini, Jonathan L.; Owen, Katharine R.; Knight, Beatrice; Cardon, Lon R.; Walker, Mark; Hitman, Graham A.; Morris, Andrew D.; Doney, Alex S. F.; McCarthy, Mark I.; Hattersley, Andrew T.
Abstract
The molecular mechanisms involved in the development of type 2 diabetes are poorly understood. Starting from genome-wide genotype data for 1924 diabetic cases and 2938 population controls generated by the Wellcome Trust Case Control Consortium, we set out to detect replicated diabetes association signals through analysis of 3757 additional cases and 5346 controls and by integration of our findings with equivalent data from other international consortia. We detected diabetes susceptibility loci in and around the genes CDKAL1, CDKN2A/CDKN2B, and IGF2BP2 and confirmed the recently described associations at HHEX/IDE and SLC30A8. Our findings provide insight into the genetic architecture of type 2 diabetes, emphasizing the contribution of multiple variants of modest effect. The regions identified underscore the importance of pathways influencing pancreatic beta cell development and function in the etiology of type 2 diabetes.
Replication of 13 genome-wide association (GWA)-validated risk variants for type 2 diabetes in Pakistani populations
DIABETOLOGIA
Authors: Rees, S. D.; Hydrie, M. Z. I.; Shera, A. S.; Kumar, S.; O'Hare, J. P.; Barnett, A. H.; Basit, A.; Kelly, M. A.
Abstract
Recent genome-wide association (GWA) studies and subsequent replication studies have greatly increased the number of validated type 2 diabetes susceptibility variants, but most of these have been conducted in European populations. Despite the high prevalence of the disease in South Asians, studies investigating GWA-validated type 2 diabetes risk variants in this ethnic group are limited. We investigated 30 single nucleotide polymorphisms (SNPs), predominantly derived from recent GWA studies, to determine if and to what extent these variants affect type 2 diabetes risk in two Punjabi populations, originating predominantly from the District of Mirpur, Pakistan. Thirty SNPs were genotyped in 1,678 participants with type 2 diabetes and 1,584 normoglycaemic control participants from two populations; one resident in the UK and one indigenous to the District of Mirpur. SNPs in or near PPARG, TCF7L2, FTO, CDKN2A/2B, HHEX/IDE, IGF2BP2, SLC30A8, KCNQ1, JAZF1, IRS1, KLF14, CHCHD9 and DUSP9 displayed significant (p < 0.05) associations with type 2 diabetes, with similar effect sizes to those seen in European populations. A constructed genetic risk score was associated with type 2 diabetes (p = 5.46 x 10(-12)), BMI (p = 2.25 x 10(-4)) and age at onset of diabetes (p = 0.002). We have demonstrated that 13 variants confer an increased risk of type 2 diabetes in our Pakistani populations; to our knowledge this is the first time that SNPs in or near KCNQ1, JAZF1, IRS1, KLF14, CHCHD9 and DUSP9 have been significantly associated with the disease in South Asians. Large-scale studies and meta-analyses of South Asian populations are needed to further confirm the effect of these variants in this ethnic group.
COA
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