title: Heritability of endometriosis.
abstract: OBJECTIVE
  To estimate the relative contribution of genetic influences and prevalence on endometriosis.
  
  
  METHODS
  Analysis of self-reported data from a nationwide population-based twin registry.
  
  
  METHODS
  Not applicable.
  
  
  METHODS
  A total of 28,370 women, female monozygotic (MZ) or dizygotic (DZ) twins, who participated in either of two surveys (1998-2002 or 2005-2006).
  
  
  METHODS
  None.
  
  
  METHODS
  Self-reported endometriosis, validated by medical records.
  
  
  RESULTS
  A history of endometriosis was reported by 1,228 female twins. The probandwise concordance was 0.21 for MZ and 0.10 for DZ twins. Higher within-pair (tetrachoric) correlation was observed among MZ (0.47) compared with DZ (0.20) twins. The best-fitting model revealed a contribution of 47% by additive genetic factors and the remaining 53% attributed to unique environmental effects.
  
  
  CONCLUSIONS
  Our findings suggest both genetic and unique (nonshared) environmental influences on the complex etiology of endometriosis and support the hypothesis that genes have a strong influence on phenotypic manifestations of endometriosis.
authors.affiliation: Department of Clinical Science and Education, Karolinska Institutet, Stockholm, Sweden. Electronic address: rama.saha@ki.se.
authors.forename: Rama
authors.initials: R
authors.lastname: Saha
authors.affiliation: Department of Clinical Science and Education, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Hans Järnbert
authors.initials: HJ
authors.lastname: Pettersson
authors.affiliation: Division of Insurance Medicine, Department of Clinical Neurosciences, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Pia
authors.initials: P
authors.lastname: Svedberg
authors.affiliation: Department of Women's and Children's Health, Uppsala University, Uppsala, Sweden.
authors.forename: Matts
authors.initials: M
authors.lastname: Olovsson
authors.affiliation: Karolinska Institutet, Stockholm, Sweden.
authors.forename: Agneta
authors.initials: A
authors.lastname: Bergqvist
authors.affiliation: Department of Clinical Science and Education, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Lena
authors.initials: L
authors.lastname: Marions
authors.affiliation: Department of Clinical Science and Education, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Per
authors.initials: P
authors.lastname: Tornvall
authors.affiliation: Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Ralf
authors.initials: R
authors.lastname: Kuja-Halkola
mesh_terms: D000328:Adult; D000368:Aged; D003430:Cross-Sectional Studies; D004200:Diseases in Twins / Q000453:epidemiology / Q000235:genetics; D004715:Endometriosis / Q000453:epidemiology / Q000235:genetics*; D005260:Female; D020022:Genetic Predisposition to Disease; D006801:Humans; D008875:Middle Aged; D008957:Models, Genetic; D019655:Quantitative Trait, Heritable; D014429:Twins, Dizygotic / Q000235:genetics / Q000706:statistics & numerical data; D014430:Twins, Monozygotic / Q000235:genetics / Q000706:statistics & numerical data; D055815:Young Adult
keywords: Concordance; endometriosis; heritability; twins