OrganismHomo sapiens
Aging PhenotypeCorrelation
Allele TypeUnknown
DescriptionAmong a U.S.-based group of long-lived individuals, there is a statistically significant under-representation of a risk allele of MTP (Geesaman et al., 2003).
This finding was not replicated in a French-based longevity study; however this discrepancy could be due to a lack of statistical power due to sample size (Geesaman et al., 2003). A more recent study also failed to find a significant correlation between MTP haplotype and longevity in a study of 1589 German nonagenerians, centenarians, and appropriately matched controls (Nebel et al., 2005). In comparison with all other U.S. and European samples analyzed, the MTP risk haplotype was found to be overrepresented only in the U.S. controls, which the authors interpret to suggest that the association is more likely to reflect recent changes in the genetic structure of the U.S. Caucasian population as a whole, rather than genetic effects upon survival to old age.
An unknown locus on chromosome 4 was previously found to be associated with long life-span among centenarians (Puca et al., 2001). Geesamen et al. (2003) identify that locus as MTP.
Gene FunctionMicrosomal transfer protein. The rate limiting step in lipoprotein synthesis.
Other PhenotypesHumans homozygous for two non-functioning alleles of MTP suffer from abetalipoproteinemia and lack ApoB particles in serum.
Drugs that inhibit can MTP improve lipoprotein profiles.
Primary ReferenceGeesaman, B. J., E. Benson, S. J. Brewster, L. M. Kunkel, H. Blanche et al., 2003 Haplotype-based identification of a microsomal transfer protein marker associated with the human lifespan. Proc Natl Acad Sci U S A .11778046 [Abstract]
Other ReferencesPuca, A. A., Daly, M. J., Brewster, S. J., Matise, T. C., Barrett, J., Shea-Drinkwater, M., Kang, S., Joyce, E., Nicoli, J., Benson, E., Kunkel, L. M., and Perls, T. (2001). A genome-wide scan for linkage to human exceptional longevity identifies a locus [Abstract]
Nebel, A., Croucher, J. P., Stiegeler, R., Nikolaus, S., Krawczak, M., and Schreiber, S. (2005). No association between microsomal triglyceride transfer protein (MTP) haplotype and longevity in humans. Proc Natl Acad Sci U S A 102, 7906-7909.
Relevant LinksOMIM:
KeywordsSNP, allele, mapping, H. sapiens, human