Twin Research

Articles

Infant zygosity can be assigned by parental report questionnaire data

Thomas S Pricea1 c1, Bernard Freemana2, Ian Craiga3, Stephen A Petrilla4, Lorna Ebersolea5 and Robert Plomina6

a1 Social Genetic and Developmental Psychiatry Research Centre, Institute of Psychiatry, London, UKt.price@iop.kcl.ac.uk

a2 Social Genetic and Developmental Psychiatry Research Centre, Institute of Psychiatry, London, UK

a3 Social Genetic and Developmental Psychiatry Research Centre, Institute of Psychiatry, London, UK

a4 Wesleyan University, Middletown, CT, USA

a5 Social Genetic and Developmental Psychiatry Research Centre, Institute of Psychiatry, London, UK

a6 Social Genetic and Developmental Psychiatry Research Centre, Institute of Psychiatry, London, UK

Abstract

A parental report questionnaire posted to a population sample of 18-month-old twins correctly assigned zygosity in 95%of cases when validated against zygosity determined by identity of polymorphic DNA markers. The questionnaire was as accurate when readministered at 3 years of age, with 96% of children being assigned the same zygosity on both occasions. The results validate the use of parental report questionnaire data to determine zygosity in infancy. Twin Research (2000) 3, 129–133.

(Revised November 18 1999)

(Revised March 14 2000)

(Accepted March 22 2000)

Keywords

  • zygosity;
  • twin;
  • infancy;
  • DNA

Correspondence:

c1 Correspondence: Thomas S Price, Social Genetic and Developmental Psychiatry Research Centre, Institute of Psychiatry, London, SE5 8AF, UK. Tel: + 44 (0) 207 848 0961; Fax: + 44 (0) 207 848 0866

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