Validation of a telephone zygosity questionnaire in twins of known zygosity.
The aim of this study was to validate a zygosity questionnaire that can be administered over the telephone. Mothers of same-sexed twins of known zygosity and chronicity between 2 and 31 years of age were interviewed on a nine-item questionnaire. From the answers one unweighted and four weighted indices were computed. As single questions, the mother's opinion and the "two peas in a pod" question differentiated best between monozygotic and dizygotic twins. One independent well-trained observer assessed the zygosity based on the questionnaire and made the correct diagnosis in 96% of the cases. A weighted index of eight similarity questions yielded an accuracy of 98%. This study shows that the zygosity of same-sexed twins more than 2 years old and without gross physical malformation can reliably be determined by a telephone questionnaire with a high accuracy.
Center for Human Genetics, Katholieke Universiteit Leuven, Belgium.
H
H
Peeters
S
S
Van Gestel
R
R
Vlietinck
C
C
Derom
R
R
Derom
D000293:Adolescent; D000328:Adult; D016009:Chi-Square Distribution; D002648:Child; D002675:Child, Preschool; D005069:Evaluation Studies as Topic; D005260:Female; D006801:Humans; D016013:Likelihood Functions; D008297:Male; D015203:Reproducibility of Results; D011795:Surveys and Questionnaires / Q000592:standards*; D013689:Telephone; D018433:Twin Studies as Topic / Q000379:methods*; D014429:Twins, Dizygotic / Q000145:classification*; D014430:Twins, Monozygotic / Q000145:classification*