Identification of two polymorphisms in the promoter of the microsomal triglyceride transfer protein (MTP) gene: lack of association with lipoprotein profiles.

The microsomal triglyceride transfer protein (MTP) catalyzes the transfer of triglyceride, cholesteryl ester, and phosphatidylcholine between phospholipid surfaces. The 97-kD subunit imparts lipid transfer activity and thus plays a role in the assembly of apolipoprotein B (apoB)-containing lipoproteins. We tested whether polymorphisms in the promoter region of the large subunit of the MTP gene might be related to different plasma lipid variables, atherosclerosis, and the risk of myocardial infarction (MI). We screened 838 bp in the promoter region of the MTP gene by PCR-SSCP and identified two polymorphisms at positions -400 (MTP/-400 (A-->t)) and -164 (MTP/-164 (T-->c)), the latter being situated on a putative sterol responsive element (SRE) consensus sequence. The two polymorphisms, investigated in 622 male patients with MI and in 728 age-matched controls participating in the ECTIM Study, were in nearly complete linkage disequilibrium (|D'| = +0.98, less frequent alleles being preferentially associated, P < 0.001). There were no significant differences in genotype or allele frequencies between patients with MI and controls. Moreover, no significant associations between the two promoter polymorphisms and several lipid variables measured in the control groups of the ECTIM Study or coronary artery stenosis, angiographically assessed in patients with MI, were detected. We conclude that these MTP polymorphisms are unrelated to lipid variables or coronary heart disease in this study. Identification of two polymorphisms in the promoter of the microsomal triglyceride transfer protein (MTP) gene: lack of association with lipoprotein profiles.