In addition to different degrees of neuronal PTEN deficiency, the discordant results may be due to (i) the greater C57BL/6J genetic mixture in the background of our colony, which would be consistent with the susceptibility of C57BL/6J mice to insulin resistance; (ii) to the fact that our mice did not show growth retardation; or (iii) to differences in age as mice in Nguyen's study were 8 to 10 weeks old (47), whereas mice in ours were 11 to 13 weeks old. This evidence concerns the gene PTEN and Insulin resistance.