Scientists have identified variants that increase risk of type 2 diabetes in populations of both East Asian and European origin. Each copy of one of these risk variants increases an individual’s odds of getting the disease by 30?40%, an effect that exceeds all of the other susceptibility genes identified to date, with the exception of TCF7L2.
Online in Nature Genetics this week two groups report genome-wide association studies of Japanese individuals with type 2 diabetes. Masato Kasuga and colleagues found variants in KCNQ1 to be associated with increased risk of the disease, which they subsequently replicated in populations from Korea, China and Sweden. Shiro Maeda also identified risk variants in KCNQ1 in Japanese, and replicated the associations in affected individuals from Singapore and Denmark. KCNQ1 encodes a potassium channel subunit, and although KCNQ1 mutations have most prominently been associated with life-threatening cardiac arrhythmias, the gene has also been reported to regulate insulin secretion in the pancreas.
The risk variants have a similar effect in both East Asian and European populations, but they are much less frequent in Europeans, which may explain why they were not previously identified in the European-based large-scale studies of type 2 diabetes. As such, these results add to the growing body of evidence that the frequency of disease susceptibility variants may differ depending on ancestry, and underscore the importance of carrying out genome-wide association studies of individuals of non-European descent.
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