MTP gene polymorphisms and postprandial lipemia in familial combined hyperlipidemia: effects of treatment with atorvastatin.

BACKGROUND The microsomal triglyceride transfer protein (MTP) is involved in hepatic and intestinal apoB secretion. We studied the effect of the functional MTP-493G/T polymorphism on fasting and postprandial lipoproteins in patients with familial combined hyperlipidemia (FCH) before and after treatment with atorvastatin. METHODS Eight FCH heterozygote carriers of the rare -493T allele were compared to 9 matched FCH homozygotes for the wild-type allele in a pilot study. Oral fat loading tests were carried out to measure triglycerides (TG) and apo B48 and B100 in the different fractions of triglyceride-rich lipoproteins (TRLs) before and after treatment with atorvastatin. RESULTS Before treatment, TG were similar between the -493T allele carriers and non-carriers. In the T-allele carriers, a trend was observed for increased postprandial apo B48 and B100 concentrations in Sf >400 and Sf 60-400 compared to non-carriers. After treatment, fasting and postprandial TG were significantly lowered in carriers of the T allele, but atorvastatin had no effect on postprandial TG in non-carriers. Atorvastatin resulted in similar reductions of apo B48 and B100 in TRLs in both groups. CONCLUSION The MTP-493G/T polymorphism modulates postprandial apo B48 and apo B100 of TRLs in FCH. Atorvastatin decreases postprandial TG in T-allele carriers with FCH.