title: Prevalence of premature ovarian failure in monozygotic and dizygotic twins.
abstract: BACKGROUND
  Premature ovarian failure (POF) before 40 years of age from natural causes affects approximately 1% of adult women, with minor variations between ethnic groups. A recent case of ovarian transplantation between young monozygotic (MZ) twins in which one had undergone unexplained POF at 14 years has prompted a study of the prevalence of POF.
  
  
  METHODS
  Menopausal ages of 832 Australian and UK female twin-pairs were extracted from volunteer national twin registry databases containing medical, reproductive and lifestyle data surveyed by mail questionnaire. Surgical menopause was an exclusion criterion.
  
  
  RESULTS
  The prevalence of POF in both MZ and dizygotic (DZ) twins was similar in both registries and 3- to 5-fold greater than the general population at age thresholds 40 and 45 years. No specific factors were found to account for the higher risk of early menopause. Some twins of both zygosities were highly discordant for menopausal age (>or=10 years). Nevertheless, there was significant intra-twin dependence, especially for MZ twins, and the average age difference at last menses was greater in DZ twin-pairs.
  
  
  CONCLUSIONS
  Both MZ and DZ twins are at higher risk of POF. Despite some striking differences within MZ twin-pairs, menopausal ages were more concordant than for DZ twin-pairs, confirming that the timing of menopause has a heritable component.
authors.affiliation: Center for Reproductive Medicine and Infertility, Weill Medical College of Cornell University, New York, NY 10021, USA. rgg2004@med.cornell.edu
authors.forename: R G
authors.initials: RG
authors.lastname: Gosden
authors.forename: S A
authors.initials: SA
authors.lastname: Treloar
authors.forename: N G
authors.initials: NG
authors.lastname: Martin
authors.forename: L F
authors.initials: LF
authors.lastname: Cherkas
authors.forename: T D
authors.initials: TD
authors.lastname: Spector
authors.forename: M J
authors.initials: MJ
authors.lastname: Faddy
authors.forename: S J
authors.initials: SJ
authors.lastname: Silber
mesh_terms: D000328:Adult; D001315:Australia / Q000453:epidemiology; D004200:Diseases in Twins / Q000453:epidemiology*; D005260:Female; D006801:Humans; D008593:Menopause; D008875:Middle Aged; D015995:Prevalence; D016649:Primary Ovarian Insufficiency / Q000453:epidemiology*; D014429:Twins, Dizygotic; D014430:Twins, Monozygotic; D006113:United Kingdom / Q000453:epidemiology