Hlne Blanch

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Genetics of Longevity

• Hélène Blanché
• Fondation Jean Dausset - CEPH

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Longevity a complex trait

• Twin study 2872 Danish pairs (Herskind et al.
  1996)
• Heritability 0.25
• Siblings of centenarians are 8 17 more likely
  to become centenarian as compared to controls
  (Perls et al. 2002)
• Association study
• Linkage analysis

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Collection of biological samples

• Started at CEPH in 1991
• DNA, plasma, serum, PBL, lymphoblastoïd cell
  lines
• 980 unrelated centenarians
• 500 nonagenarians belonging to 240 families
• 550 offspring of nonagenarians belonging to 180
  families

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Cohorts available

• Japan
• China
• Germany
• United Kingdom
• Italy
• Denmark
• Finland
• Netherlands
• United States

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Main results of association studies

• Lots of associations which were never clearly
  replicated except for APOE, frailty gene.
• Genes tested at CEPH (between 1997 and 2000)
• APOE
• ACE
• WRN
• LMNA
• TERT, TERC
• KLOTHO
• SOD2, SOD3
• GSR, CAT, GPX1, GPX3, CYP2D6, GSTM1, NAT2

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Linkage studies

• A linkage signal on chromosome 4q published by
  Puca et al. in 2001.
• 308 nonagenarians, 138 families
• Not yet confirmed.
• MTP (microsomal transfer protein) was found
  associated with longevity in a US population. Not
  confirmed in French, Danish, German, Dutsch
  cohorts

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GEHA (Genetics of Healthy Aging)

• Started in 2004
• Integrated Project of EU 6thFP
• 5 years, 25 Partners.

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Aims of GEHA

• To recruit 2650 sib-pairs of elderly people and
  2650 matched younger controls
• To search for candidate regions/genes
• To test whether different populations share the
  same genes involved in aging and longevity
• To identify mtDNA haplogroups and mtDNA mutations
  associated with longevity
• To identify gender-specific genes differently
  involved in healthy aging and longevity

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Set up of a standardized protocol

• Acceptable by all local ethics committees
• Informed consent, information file
• Standardized case sheet to assess and record data
  
• socio-demographic information,
• lifestyle habits,
• health and morbidity,
• medication,
• sensorial function,
• cognitive function and depression (SMMSE),
• functional activity, physical performances (ADL
  test, Hand grip test, Chair stand test).
• Training of people in charge of the recruitment

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A phenotypic database

• Centralized database in Odense and local data
  stored in each recruiting center
• EPIDATA, a standardized procedure to enter data
  online via a VPN (crypted connection) to the
  centralized database
• Restricted access by login/password

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Recruitment identification of volunteers

• Identification of elderly sib-pairs
• On census data or other available lists
• Contact people by phone or mail
• Visit at elderlys home, nursing home
• Identification of unrelated controls (60-75 years
  old)

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Organization of a visit

• Interview of the volunteer in presence of a proxy
  if necessary (MD or trained nurse)
• Presentation of the project
• Answer to all questions
• Informed consent is signed
• Collect of information
• Cognitive and physical tests
• Collect of biological sample
• About 2 hours per volunteer

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Biological samples and treatments

• 2 EDTA tubes labeled with bar codes (PID)
• - one is frozen without any treatment for further
  DNA extraction
• - one is centrifuged to isolate plasma and blood
  pellet
• 3rd tube either EDTA or heparin, labeled with bar
  code (PID)
• - isolation of plasma and blood pellet
• - isolation of PBL for establishment of cell
  lines
• Cheek swab if blood donation is not possible

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Update on recruitment, March 2006

• 3500 families contacted
• 40.7 gave a positive answer
• 51 were excluded
• 9.7 one sib died
• 11.1 dementia
• 27.5 immediate refusal
• 2.7 one sib was unreachable
• 8.3 of contacted families are in stand-by
• 881 sib-pairs and 881 controls were recruited

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KTL a centralized DNA extraction center

• For each individual, one frozen whole blood
  sample is sent to KTL
• Extractions are performed on a Gentra automate
• Each DNA is labeled with a new ID (GID). KTL has
  the correspondence table between PID and GID
• 943 DNAs were extracted (including 19 cheek swab
  samples) (March 2006)

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9 Genetic Platforms
Mitochondrial genome
Nuclear genome
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A genotypic database

• Centralized in Kiel Genedigger
• Connections between phenotypic and genotypic
  databases only allowed for partners involved in
  analyses after approval of the Steering Committee

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Genome scan

• Illumina Linkage panel
• 136 sib-pairs are genotyped at CNG
• 600 next sib-pairs should be available in
  September 2006
• Analyses on 736 sib-pairs will be performed at
  the end of 2006.

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Association studies

• Chr4q region (linkage data)
• Chr11p15.5 region (SIRT3, KRAS, IGF2, INS, TH),
  a 2.4 Mb region.

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Chr11p15.5 region selection of SNPs

• Search for TagSNP typed for the HapMap project
  (build 34), 30 CEPH trios
• LDselect (Carlson)
• Analysis of 587 SNPs (MAF 5 )
• 337 TagSNPs were identified

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Chr11p15.5 region results

• Germany 377 cases and 376 controls
• Central Italy 307 cases and 352 controls
• 214 SNPs out of 337 TagSNPs were typed
  successfully on cohorts
• No association was identified in one population
  and replicated in the other
• Replication on French centenarians and controls?

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Future of genetic studies in GEHA

• Genome scan
• Analysis of 736 sib-pairs
• Confirmation of positive signals on a new
  sib-pair population
• Association study
• French cohort tested on positive signals
  identified on either German or Central-Italian
  cohorts
• Follow up of candidate regions identified during
  the genome scan

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Acknowledgments

• GEHA main collaborators
• Claudio Franceschi, University of Bologna
• Stefan Schreiber, University Hospital Schleswig
  Holstein, Kiel
• Eline Slagboom, Leiden University Medical Center
• Markus Perola, KTL, Helsinki
• CEPH
• Jean-Christophe Beaudoin
• Laetitia Gressin
• Valérie Morel
• Patricia Pasturaud
• Mourad Sahbatou
• Mark Lathrop