The correlation of HOMA-AD values with diabetes mellitus markers, FBG, post dextrose glucose, and HbA1c in addition to HOMA-IR values, levels of adiponectin, leptin, and visfatin, and ALR reinforce the hypothesis that the characteristics observed in patients with NF1 (lower levels of FBG, visfatin, and leptin and higher adiponectin and adiponectin/leptin levels) may explain the lower incidence of T2DM in these patients. This evidence concerns the gene LEP and Alzheimer disease.