309 ISSN 1758-1907 10.2217/DMT.11.14 © 2011 Future Medicine Ltd Diabetes Manage. (2011) 1(3), 309–324 SUMMARY Type 2 diabetes (T2D) is a polygenic disorder with multiple genes located on diferent chromosomes contributing to its susceptibility. Analysis of the genetic factors is further complicated by the fact that numerous environmental factors interact with genes to produce the disorder. Only a minority of cases of T2D such as maturity-onset diabetes of the young are caused by single gene defects. As Asian Indians have an increased susceptibility to diabetes and have increased insulin resistance, they are a unique population for carrying out genetic studies. Asian Indians develop T2D at lower levels of BMI, one to two decades earlier and have stronger heritability factors compared with Europeans. All these factors point to the role of possible ethnic variations in genetic susceptibility. Recent genetic studies on Asian Indians indicate that certain genes appear to predispose Indians to diabetes while other genes, which aford protection against diabetes and insulin resistance to Caucasians, do not appear to protect Indians. In addition, there are several genes (e.g., TCF7L2), which are similar in Asian Indians and in Europeans, that contribute to susceptibility to T2D. Advances in genotyping techniques and the availability of large patient cohorts have made it possible to identify common genetic variants associated with T2D through genome-wide association studies. Recent studies have shown that common genetic variations contribute to T2D risk within populations but do not explain the diference between populations. In this context, the risk allele evaluation of T2D in Asian Indians could help provide better understanding of increased susceptibility to T2D within this ethnic group. 1 Madras Diabetes Research Foundation, ICMR Advanced Centre for Genomics of Type 2 diabetes, No. 4, Conran Smith Road, Gopalapuram, Chennai - 600 086, India 2 Dr Mohan’s Diabetes Specialities Centre, WHO Collaborating Centre For Non Communicable Diseases Prevention & Control, IDF Centre for Education, Chennai, India; † Author for correspondence: Tel.: +91 444 396 8888; Fax: +91 442 835 0935; drmohans@diabetes.ind.in  The etiopathogenesis of Type 2 diabetes involves the interplay of both genetic and environmental factors.  Asian Indians have certain unique clinical and biochemical characteristics that are collectively referred to as the ‘Asian Indian phenotype’.  The genetics of Type 2 diabetes can be of two broad groups: genetics of monogenic forms and polygenic forms of diabetes.  Identifcation of rarer monogenic forms of diabetes such as maturity-onset diabetes of the young and neonatal diabetes could help plan treatment more accurately.  Certain genes appear to uniquely predispose Asian Indians to Type 2 diabetes.  To identify the complex individual susceptible and protective genes, a full understanding of the complex gene–gene and gene–environment interactions is required. Practice Points Genetics of Type 2 diabetes in Asian Indians REVIEW V Radha 1 , S Kanthimathi 1 & V Mohan †1,2