Design of Arab Diabetes Gene-Centric Array (ADGCA) in population with an epidemic of Type 2 Diabetes: A population specific SNP evaluation

In the case of diabetes and other complex diseases, the challenge has always been to find genetic markers that explain the excess risk associated with development of the disease. In the last 12 years, advances in genotyping technology provided substantial development in the discovery of loci contributing to Type 2 diabetes (T2D) susceptibility. Therefore, the aim of this study is to custom design, for the first time in Arab world, an “Arab Diabetes Gene Centric Array” (ADGCA) that assays 643, 745 SNP markers including 50,617 diabetes associated SNPs. The array content was designed after comprehensive literature search prioritizing Diabetes associated SNPs. PCA was performed to evaluate the relationship between world populations and the Saudi population in building the backbone for the array. A genotype data matrix for PCA analysis was produced by including the genotypes of the 270 HapMap samples including JPT, CHB, YRI and CEU to genotypes of the 1457 Saudi samples. Imputation was executed using IMPUTE2 software and the 1000GP Phase III reference panel. All markers incorporated to ADGCA were validated. Quality checks and evaluation of its capacity and performance as a platform for genetic screening for T2D was performed using the latest stastical tools available. We were successful in designing ADGCA as a custom made chip array designed with a motive to capture genetic variation in loci known or reported to be associated with the development of T2D. However, implementation of ADGCA is currently being performed by our research group using 2000 DNA samples respectively from diabetic and non diabetic individuals which could further validate the use of ADGSA in genetic screening of T2D.