Swedish Twin Registry - STR
HISTORY
• Started by Lars Friberg and Rune Cederlöf in the late
1950’s
• Church records of twin births 1886-1925
• All identified same sex twins contacted during the
1960’s
• Today: all alive Swedish born twins aged 10 or more
have been contacted and asked for participation
Steering group
• Steering group: Patrik Magnusson (director)
Nancy Pedersen, Paul Lichtenstein, Martin
Schalling, Maria Feychting, Laura Fratiglioni,
Johan Askling, Tomas Ekström, Mikael
Norman, Olli Kallioniemi
• Evaluation of applications
• Meetings 4 times per year
The Swedish Twin Registry –
Historical cohort compilations and contacts
Birth cohort
2004-2006
1986-2004
1959-1985
1926-1958
1886-1925
1960
1970
1980
1990
2000
2010
Current ascertainment into STR
• Since 2004 we systematically contact parents
to Swedish born twins when they turn 9 years
of age
• Request to participate in STR – broad consent
• Screen for somatic and mental health problem
• High participation rate (70-80%)
• Follow-up’s at 12, 15, 18 years
Recent “Landmark”
• All adult Swedish born twins 10 years or older
have now been contacted for participation with
general questionnaire and DNA donation request
• 200 000 in the register
• 150 000 have zygosity
• The largest twin register in the world
Data
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Paper Questionnaires
Telephone interviews (SALT 1998-2002)
Web questionnaires (2005 and onwards)
Health check-up (TwinGene, CATSS, SATSA)
Health registers (SoS)
DNA (N=50 000)
GWAS (N=33 000, 27 000 not counting MZ twice)
Serum (N=15 000)
Blood biochemistry (TwinGene, SATSA)
Computer tests (cognition, time-consistency)
GWAS
• Older cohort (1911-1958):
– Illumina GWAS array N = 20 000
– Excl. redundant MZ genomes N = 16 000
– Genotyped in Uppsala (SNP&SEQ Tech) 2008,
2011, 2015
• Younger cohort (1994 -- )
– Illumina GWAS array N = 13 000
– Excl. redundant MZ genomes N=11 000
– Genotyped in Uppsala (SNP&SEQ Tech) 2015
Serum measurements
• All of TwinGene (N=12600)
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HDL, LDL, TC, TG, CRP, Hb, HbA1c, Glucose, ApoA1, ApoB
ACPA (Lars Klareskog)
Total IgA (Lennart Hammarström)
Creatinine, Cystatin C (Per Svensson)
• Subsets
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LpPla2, aPC, aOxCl (Ulf de Faire, Johan Frostegård)
PCSK9 (Anders Hamsten)
Proteomics (SciLife Lab Protein atlas)
Metabolomics (HPLC Mass spec)
Serum is an available but limited resource - should be used thoughtfully!
Epigenetics
• Key observations:
– Gene expression differs between cell types within
individual
– MZ twins - discordant
– Gene expression influenced by environment
• Measure Epigenetics:
– DNA methylation, histone acetylation etc.
• Confounding from Genetics:
– MZ twins may provide remedy!
Applying for new projects
• STR steering committee meets 4 times/year
• Short application + CV + ethics permission
http://ki.se/forskning/for-forskare-str
• metadata + questionnaires assessable for free
• Blood, serum and DNA stored in biobank
• Phenotypes