Mutation not universally linked with diabetes

Sir

Pierre Maechler and Claes B. Wollheim¹ in their interesting Insight Review Article on mitochondrial function in normal and diabetic β-cells show diabetes-associated mutations in the human mitochondrial genome in their Fig. 1. One of these mutations is G3316A in the ND1 gene (references cited in ref. 1).

Until recently, this mutation had been reported only in a Japanese population. Since then, other independent studies^2,3 have not found this association between G3316A and diabetes in Chinese people or in another Japanese population⁴.

Because about 4% of China's 1.2 billion people carry this mutation², it is important that the polymorphism G3316A is not regarded as diabetes-associated outside the Japanese population reported in ref. 1.