HMGCR and familial hypercholesterolemia: It has been demonstrated that Pb can increase the production of cholesterol, leading to hypercholesterolemia by the upregulation of HMG-CoA reductase, an enzyme involved in the biosynthesis of cholesterol (47), and Mg also plays a vital role in the rate-limiting step in cholesterol synthesis at HMG-Co A reductase (40).