Genetic Studies of Type 2 Diabetes in South Asians: A Systematic Overview
Ritam Chowdhury, Kabayam M. Venkat Narayan, Azadeh Zabetian, Suraja Raj and Rubina Tabassum
Affiliation: Institute for Molecular Medicine Finland, University of Helsinki, Biomedicum 2U, Tukholmankatu 8, 00290 Helsinki.
Diabetes Mellitus, which affects 366 million people worldwide, is a leading cause of mortality, morbidity, and
loss of quality of life. South Asians, comprising 24% of the world’s population, suffer a large burden of type 2 diabetes.
With intriguing risk phenotypes, unique environmental triggers, and potential genetic predisposition, South Asians offer a
valuable resource for investigating the pathophysiology of type 2 diabetes. Genomics has proven its potential to underpin
some of the etiology of type 2 diabetes by identifying a number of susceptibility genes, but such data are scarce and unclear
in South Asians. We present a systematic review of studies on the genetic basis of type 2 diabetes or its complications
in South Asians published between 1987-2012, and discuss the findings and limitations of the available data. Of the
91 eligible studies meeting our inclusion criteria, a vast majority included Indian populations, followed by a few in those
of Pakistani origin, while other South Asian countries were generally under-represented. Though a large number of studies
focused on the replication of findings from genome-wide association studies (GWAS) in European populations, a few
studies explored new genes and pathways along with GWAS in South Asians and suggested the potential to unravel population-
specific susceptibility genes in this population. We find encouraging improvements in study designs, sample sizes
and the numbers of genetic variants investigated over the last five years, which reflect the existing capacity and scope for
large-scale genetic studies in South Asians.
Keywords: Type 2 diabetes, genetics, south asians, systematic review.
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