Polymorphism of the apolipoprotein B gene and blood lipid concentrations in Japanese and Caucasian population samples.

To examine whether a racial difference in apolipoprotein B (Apo B) gene polymorphism between Japanese and American Caucasians corresponds with the lower blood cholesterol concentrations in Japanese than in Americans, we examined the EcoRI polymorphism of the Apo B gene for 271 nonsmoking men and women aged 47-69 years in two population-based samples: rural Japanese living in Akita and Caucasians living in Minneapolis-St. Paul, Minnesota, USA. Mean values of serum cholesterol concentrations were significantly lower in Japanese than in Caucasians for both men and women (difference = 25-26 mg/dl). An allele-specific polymerase chain reaction was conducted to examine the Eco RI cutting site at the 12669 cDNA position of the Apo B gene. The allele R2 (absence of the cutting site) has been associated with lower cholesterol concentrations in two previous studies. The frequency of the R2 allele was 6% for Japanese and 17% for Caucasians (P