title: Identification of quantitative trait loci for fibrin clot phenotypes: the EuroCLOT study.
abstract: OBJECTIVE
  Fibrin makes up the structural basis of an occlusive arterial thrombus, and variability in fibrin phenotype relates to cardiovascular risk. The aims of the current study from the EU consortium EuroCLOT were to (1) determine the heritability of fibrin phenotypes and (2) identify QTLs associated with fibrin phenotypes.
  
  
  RESULTS
  447 dizygotic (DZ) and 460 monozygotic (MZ) pairs of healthy UK white female twins and 199 DZ twin pairs from Denmark were studied. D-dimer, an indicator of fibrin turnover, was measured by ELISA and measures of clot formation, morphology, and lysis were determined by turbidimetric assays. Heritability estimates and genome-wide linkage analysis were performed. Estimates of heritability for d-dimer and turbidometric variables were in the range 17% to 46%, with highest levels for maximal absorbance which provides an estimate of clot density. Genome-wide linkage analysis revealed 6 significant regions with LOD >3 on 5 chromosomes (5, 6, 9, 16, and 17).
  
  
  CONCLUSIONS
  The results indicate a significant genetic contribution to variability in fibrin phenotypes and highlight regions in the human genome which warrant further investigation in relation to ischemic cardiovascular disorders and their therapy.
authors.affiliation: Department of Twin Research and Genetic Epidemiology, King's College London, St Thomas' Hospital, London, UK. frances.williams@kcl.ac.uk
authors.forename: Frances M K
authors.initials: FM
authors.lastname: Williams
authors.forename: Angela M
authors.initials: AM
authors.lastname: Carter
authors.forename: Bernet
authors.initials: B
authors.lastname: Kato
authors.forename: Mario
authors.initials: M
authors.lastname: Falchi
authors.forename: Lise
authors.initials: L
authors.lastname: Bathum
authors.forename: Gabriela
authors.initials: G
authors.lastname: Surdulescu
authors.forename: Kirsten Ohm
authors.initials: KO
authors.lastname: Kyvik
authors.forename: Aarno
authors.initials: A
authors.lastname: Palotie
authors.forename: Tim D
authors.initials: TD
authors.lastname: Spector
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Grant
mesh_terms: D000328:Adult; D001777:Blood Coagulation / Q000235:genetics*; D002318:Cardiovascular Diseases / Q000097:blood / Q000235:genetics*; D003718:Denmark; D005260:Female; D005338:Fibrin Fibrinogen Degradation Products / Q000235:genetics* / Q000378:metabolism; D020022:Genetic Predisposition to Disease; D055106:Genome-Wide Association Study; D006801:Humans; D015810:Linkage Disequilibrium; D008875:Middle Aged; D010641:Phenotype; D040641:Quantitative Trait Loci; D019655:Quantitative Trait, Heritable; D012042:Registries; D013927:Thrombosis / Q000097:blood / Q000235:genetics*; D014429:Twins, Dizygotic / Q000235:genetics; D014430:Twins, Monozygotic / Q000235:genetics; D006113:United Kingdom
chemical_list: D005338:Fibrin Fibrinogen Degradation Products; C036309:fibrin fragment D