lunes, 30 de enero de 2012

PLoS ONE: Genetic Signatures of Exceptional Longevity in Humans

Genetic Signatures of Exceptional Longevity in Humans

Like most complex phenotypes, exceptional longevity is thought to reflect a combined influence of environmental (e.g., lifestyle choices, where we live) and genetic factors. To explore the genetic contribution, we undertook a genome-wide association study of exceptional longevity in 801 centenarians (median age at death 104 years) and 914 genetically matched healthy controls. Using these data, we built a genetic model that includes 281 single nucleotide polymorphisms (SNPs) and discriminated between cases and controls of the discovery set with 89% sensitivity and specificity, and with 58% specificity and 60% sensitivity in an independent cohort of 341 controls and 253 genetically matched nonagenarians and centenarians (median age 100 years). Consistent with the hypothesis that the genetic contribution is largest with the oldest ages, the sensitivity of the model increased in the independent cohort with older and older ages (71% to classify subjects with an age at death>102 and 85% to classify subjects with an age at death>105). For further validation, we applied the model to an additional, unmatched 60 centenarians (median age 107 years) resulting in 78% sensitivity, and 2863 unmatched controls with 61% specificity. The 281 SNPs include the SNP rs2075650 in TOMM40/APOE that reached irrefutable genome wide significance (posterior probability of association = 1) and replicated in the independent cohort. Removal of this SNP from the model reduced the accuracy by only 1%. Further in-silico analysis suggests that 90% of centenarians can be grouped into clusters characterized by different “genetic signatures” of varying predictive values for exceptional longevity. The correlation between 3 signatures and 3 different life spans was replicated in the combined replication sets. The different signatures may help dissect this complex phenotype into sub-phenotypes of exceptional longevity.


Paola Sebastiani1*, Nadia Solovieff1, Andrew T. DeWan2, Kyle M. Walsh2, Annibale Puca3, Stephen W. Hartley1, Efthymia Melista4, Stacy Andersen5, Daniel A. Dworkis6, Jemma B. Wilk7, Richard H. Myers7, Martin H. Steinberg6, Monty Montano6, Clinton T. Baldwin6,8, Josephine Hoh2, Thomas T. Perls5
1 Department of Biostatistics, Boston University School of Public Health, Boston, Massachusetts, United States of America, 2 Division of Chronic Disease Epidemiology, Department of Epidemiology and Public Health, Yale University School of Medicine, New Haven, Connecticut, United States of America, 3 IRCCS Multimedica, Milano, Italy; Istituto di Tecnologie Biomediche – Consiglio Nazionale delle Ricerche, Segrate, Italy, 4 Center for Human Genetics, Boston University School of Medicine, Boston, Massachusetts, United States of America, 5 Section of Geriatrics, Department of Medicine, Boston University School of Medicine and Boston Medical Center, Boston, Massachusetts, United States of America, 6 Department of Medicine, Boston University School of Medicine, Boston, Massachusetts, United States of America, 7 Department of Neurology, Boston University School of Medicine, Boston, Massachusetts, United States of America, 8 Departments of Medicine and Pediatrics, Boston University School of Medicine and Boston Medical Center, Boston, Massachusetts, United States of America

Abstract 

Like most complex phenotypes, exceptional longevity is thought to reflect a combined influence of environmental (e.g., lifestyle choices, where we live) and genetic factors. To explore the genetic contribution, we undertook a genome-wide association study of exceptional longevity in 801 centenarians (median age at death 104 years) and 914 genetically matched healthy controls. Using these data, we built a genetic model that includes 281 single nucleotide polymorphisms (SNPs) and discriminated between cases and controls of the discovery set with 89% sensitivity and specificity, and with 58% specificity and 60% sensitivity in an independent cohort of 341 controls and 253 genetically matched nonagenarians and centenarians (median age 100 years). Consistent with the hypothesis that the genetic contribution is largest with the oldest ages, the sensitivity of the model increased in the independent cohort with older and older ages (71% to classify subjects with an age at death>102 and 85% to classify subjects with an age at death>105). For further validation, we applied the model to an additional, unmatched 60 centenarians (median age 107 years) resulting in 78% sensitivity, and 2863 unmatched controls with 61% specificity. The 281 SNPs include the SNP rs2075650 in TOMM40/APOE that reached irrefutable genome wide significance (posterior probability of association = 1) and replicated in the independent cohort. Removal of this SNP from the model reduced the accuracy by only 1%. Further in-silico analysis suggests that 90% of centenarians can be grouped into clusters characterized by different “genetic signatures” of varying predictive values for exceptional longevity. The correlation between 3 signatures and 3 different life spans was replicated in the combined replication sets. The different signatures may help dissect this complex phenotype into sub-phenotypes of exceptional longevity.

PLoS ONE: Genetic Signatures of Exceptional Longevity in Humans

No hay comentarios:

Publicar un comentario