Common polymorphism in promoter of microsomal triglyceride transfer protein gene influences cholesterol, ApoB, and triglyceride levels in young African American men - Results from the Coronary Artery Risk Development in Young Adults (CARDIA) Study

The microsomal triglyceride transfer protein (MTP) plays a key role in the assembly of apolipoprotein B (apoB)-containing lipoproteins. We investigate d the relation between lipid profiles and a common functional polymorphism (-493G/T) of the MTP gene in a large sample of young black men in the Coron ary Artery Risk Development in Young Adults (CARDIA) Study. We performed se rial cross-sectional analyses on lipids of 586 black men in 5 exams over 10 years of follow-up. Total cholesterol, LDL cholesterol, and apoB levels we re very similar between the GT and GG genotypes; therefore, the GT and GG g enotypes were combined as 1 group when the 3 phenotypes were analyzed. The results from ANCOVA showed that the TT group (prevalence 7%) had higher lev els of apoB-related lipids than did the GT+GG group: the difference in tota l cholesterol ranged from 2 (P=0.79) to 19 (P=0.002) mg/dL in exams 1 to 5; the difference in LDL cholesterol ranged from 10 (P=0.14) to 17 (P=0.003) mg/dL in exams 1 to 4, but in examination 5, the difference became negligib le. The TT group had higher levels of apoB, measured in only 2 exams, by 6 (P=0.12) and 9 (P=0.03) mg/dL. The TT group had higher levels of triglyceri des than did the TG or GG group by 3 to 34 (P=0.02 to approximate to 0.003) mg/dL in all 5 exams. HDL cholesterol and apolipoprotein A-I levels were s imilar among the 3 genotypes. Our serial cross-sectional analyses indicated that the TT genotype was associated with higher levels of total cholestero l, LDL cholesterol, triglycerides, and apoB in young black men, The broad e ffect of this polymorphism on several atherogenic traits suggests that the MTP gene could be influential in atherosclerosis.