transcription of the gene would be of particular interest. Because the htSNPs used in this study, which are in strong LD, also span the promoter of SIRT1, a significant influence of variation in this regulatory region of the gene may be excluded. However, allelic variants in direct modulators of SIRT1 may be crucial in regulating SIRT1 protein levels. In addition, variation in the broad array of SIRT1 downstream targets could also play critical roles in extending lifespan. In this study, we have demonstrated that common SIRT1 variation does not appear to be associated with exceptional human longevity, despite the fact that the gene is considered an important player in pathways that modulate lifespan in a wide range of organisms, and possibly also in humans. Acknowledgements We would like to thank all probands for their participation. We are grateful to I. Urbach, T. Henke, and T. Wesse for technical assistance. This study was funded by the Federal Ministry of Science and Education through an Explorative Project of the National Genome Research Network (NGFN-2). References Barrett, J.C., Fry, B., Maller, J., Daly, M.J. "Haploview: analysis and visualization of LD and haplotype maps." Bioinformatics 21, 263-265. The SIRT gene, human silent information regulator Sir homologue, and survivorship in the elderly. Exp. Gerontol., Tissenbaum, H.A., Guarente, L. "Increased dosage of a sir-2 gene extends lifespan in Caenorhabditis elegans." Nature, Vaziri, H., Dessain, S.K., Ng Eaton, E., Imai, S.I., Frye, R.A., Pandita, T.K., Guarente, L., Weinberg, R.A. "