Modeling extended twin family data I: Description of the cascade model

Matthew C. Keller, Sarah E. Medland, Laramie E. Duncan, Peter K. Hatemi, Michael C. Neale, Hermine H.M. Maes, Lindon J. Eaves

Research output: Contribution to journalArticlepeer-review

90 Scopus citations


The classical twin design uses data on the variation of and covariation between monozygotic and dizygotic twins to infer underlying genetic and environmental causes of phenotypic variation in the population. By using data from additional relative classes, such as parents, extended twin family designs more comprehensively describe the causes of phenotypic variation. This article introduces an extension of previous extended twin family models, the Cascade model, which uses information on twins as well as their siblings, spouses, parents, and children to differentiate two genetic and six environmental sources of phenotypic variation. The Cascade also relaxes assumptions regarding mating and cultural transmission that existed in previous extended twin family designs. The estimation of additional parameters and relaxation of assumptions is potentially important, not only because it allows more fine-grained descriptions of the causes of phenotypic variation, but more importantly, because it can reduce the biases in parameter estimates that exist in earlier designs.

Original languageEnglish (US)
Pages (from-to)8-18
Number of pages11
JournalTwin Research and Human Genetics
Issue number1
StatePublished - Feb 2009

All Science Journal Classification (ASJC) codes

  • Pediatrics, Perinatology, and Child Health
  • Obstetrics and Gynecology
  • Genetics(clinical)


Dive into the research topics of 'Modeling extended twin family data I: Description of the cascade model'. Together they form a unique fingerprint.

Cite this