As compared with whites, Japanese have a much lower body mass index and a higher prevalence of genetic cholesteryl ester transfer protein (CETP) deficiency.22 It is controversial as to whether very high levels of serum HDL-C are protective against coronary heart disease, as few epidemiologic studies have investigated the relationship between high HDL-C levels, or CETP deficiency, and CAD. This evidence concerns the gene CETP and hyperinsulinemic hypoglycemia, familial, 4.