Journals of Gerontology: BioloGical ScienceS

MICROSOMAL triglyceride transfer protein (MTP) is a lipid transfer protein found in the liver and intestine and is necessary for the proper assembly of apolipoprotein B – containing lipoproteins, very low- density lipoproteins (VLDL) , and chylomicrons ( 1). Gene association studies have linked haplotypes and single nucleotide polymorphisms (SNPs) in the MTP gene with several diseases and risk factors including fatty liver disease ( 2), atherosclerotic risk factors ( 3), type 2 diabetes ( 4) , and blood pressure ( 5). In light of its pleiotropic effects and harmful associations with many dis-eases, it was not surprising that MTP also surfaced as one of the fi rst genes linked to exceptional human longevity ( 6). Using sibpair analysis on centenarians and their siblings, Puca and colleagues ( 7) performed the fi rst genomic screen-ing for exceptional human longevity and reported linkage with a region on chromosome 4. Fine mapping of the candi