Forget-Dubois Nadine, Pérusse Daniel, Turecki Gustavo, Girard Alain, Billette Jean-Michel, Rouleau Guy, Boivin Michel, Malo Jocelyn, Tremblay Richard E
Research Unit on Children's Psychosocial Maladjustment, University of Montreal, Montreal, Canada.
Twin Res. 2003 Dec;6(6):479-85. doi: 10.1375/136905203322686464.
We compared the results of different methods for diagnosing zygosity in a sample of 237 same-sex pairs of twins assessed at 5 and 18 months of age. Despite the twins' very young age and early stage of development, physical similarity was concordant with genotyping in 91.9% of cases at 5 months and 93.8% of cases at 18 months, for a subsample of 123 and 113 pairs, respectively. This concordance rate was obtained following a case-by-case assessment of each pair's physical similarity using a shortened version of the Zygosity Questionnaire for Young Twins (Goldsmith, 1991). Taking into account the chorionicity data available from the twins' medical files, we were able to classify correctly 96% of the pairs, an accuracy rate comparable to previously reported rates obtained with older twins. Chorionicity data is especially useful since we found that monochorionic MZ twins are more difficult than dichorionic MZ twins to diagnose by physical similarity at these young ages. The relative cost-benefit of methods based on reported physical similarity and DNA analysis is discussed in light of these results.
我们比较了在237对5个月和18个月大的同性双胞胎样本中，不同合子性诊断方法的结果。尽管这些双胞胎年龄很小且处于发育早期，但在分别为123对和113对双胞胎的子样本中，5个月大时身体相似性与基因分型的一致性为91.9%，18个月大时为93.8%。该一致性率是通过使用《幼儿双胞胎合子性问卷》（戈德史密斯，1991年）的简化版对每对双胞胎的身体相似性进行逐对评估后得出的。考虑到从双胞胎医疗档案中获得的绒毛膜性数据，我们能够正确分类96%的双胞胎对，这一准确率与之前报道的年龄较大双胞胎的准确率相当。绒毛膜性数据特别有用，因为我们发现，在这些年幼的年龄，单绒毛膜单卵双胞胎比双绒毛膜单卵双胞胎更难通过身体相似性来诊断。根据这些结果，我们讨论了基于所报告的身体相似性和DNA分析的方法的相对成本效益。
