Genetic modelling of dizygotic twinning in pedigrees of spontaneous dizygotic twins

Am J Med Genet. 1996 Jan 22;61(3):258-63. doi: 10.1002/(SICI)1096-8628(19960122)61:3<258::AID-AJMG10>3.0.CO;2-S.


The inheritance of spontaneous dizygotic (DZ) twinning was investigated in 1,422 three-generation pedigrees ascertained through mothers of spontaneous DZ proband twins. DZ twinning was modelled as a trait expressed only in women. The penetrance was modelled first as a parity independent and secondly as parity dependent. The observed frequencies of maternal and paternal grandmothers with DZ twins differed significantly from the expectations under an X-linked mode of inheritance. Complex segregation analysis showed that the parity-independent phenotype of "having DZ twins" was consistent with an autosomal monogenic dominant model, with a gene frequency of 0.035 and a female-specific lifetime penetrance of 0.10. Recessive, polygenic, and sporadic models were rejected. The autosomal dominant model revealed a strong robustness against a changing population prevalence and the loss of information due to the presence of same-sexed twin pairs of unknown zygosity. When DZ twinning was modelled as a parity dependent trait, the data were compatible with an autosomal dominant model with a gene frequency of 0.306 and a penetrance of 0.03 per birth for female gene carriers.

Publication types

  • Research Support, Non-U.S. Gov't
  • Twin Study

MeSH terms

  • Cluster Analysis
  • Female
  • Fertilization
  • Gene Frequency
  • Humans
  • Male
  • Models, Genetic*
  • Pedigree
  • Prevalence
  • Twins, Dizygotic / genetics*
  • Twins, Dizygotic / statistics & numerical data