title: Endometriosis in monozygotic twins.
abstract: OBJECTIVE
  To study the reproductive and medical history of monozygotic twin sisters and mothers of patients with endometriosis.
  
  
  METHODS
  Among 515 patients with endometriosis, eight had a monozygotic twin sister all of whom had had a gynecological laparoscopy or laparotomy. In addition, five of their mothers had had a laparotomy. Details about these 13 relatives were obtained either from medical records (ten cases) or by unmistakable reports from the proband (three cases).
  
  
  RESULTS
  Six of the monozygotic twin sisters (75%) also had symptomatic endometriosis compared with 3.8% among other types of sisters (p < 0.0005). Three of the mothers (38%) had either endometriosis or adenomyosis.
  
  
  CONCLUSIONS
  This study gives support to the assumption that endometriosis has a genetic trait.
authors.affiliation: Department of Obstetrics and Gynecology, National Hospital, University of Oslo, Norway.
authors.forename: M H
authors.initials: MH
authors.lastname: Moen
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D016000:Cluster Analysis; D004200:Diseases in Twins / Q000235:genetics*; D004715:Endometriosis / Q000235:genetics*; D005260:Female; D006801:Humans; D010535:Laparoscopy; D007813:Laparotomy; D009664:Norway; D014430:Twins, Monozygotic