The D76N variant of PDX1 does not significantly alter insulin secretion or act as a high-risk susceptibility allele for late-onset type 2 diabetes as proposed previously, although we cannot exclude a minor role in increasing risk of diabetes.
Neither the D76N nor the A140T segregated with diabetes, and their transcriptional activation of the human insulin promoter expressed in vitro was indistinguishable from that of the wild type (115 +/- 21% and 84 +/- 12% vs. 100%).
The lower penetrance D76N and Q59L mutations were more prevalent and were associated with a relative risk of 12.6 for diabetes and with decreased glucose-stimulated insulin-secretion in nondiabetic subjects.