AMPD1 deficiency is one of the most common inherited defects in the Caucasian population, with approximately 2% of individuals in this ethnic group being homozygous for this gene defect, and few if any of these individuals experience any adverse effects from this enzyme deficiency [6] suggesting that not only would inhibition of AMPD have beneficial effects in patients with the metabolic syndrome and diabetes but inhibition of this enzyme may lead to few deleterious effects. This evidence concerns the gene AMPD1 and metabolic syndrome.