Zygosity diagnosis in the absence of genotypic data: An approach using latent class analysis
Zygosity diagnosis in the absence of genotypic data: An approach using latent class analysis
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DOI：
10.1375/136905203762687861
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发表时间：
2003-02-01
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影响因子：
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通讯作者：
Martin, NG
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作者：
Heath, AC;Nyholt, DR;Martin, NG
在缺乏基因型数据的情况下，或者在双胞胎研究的招募阶段，只有来自同性对的单胞胎被筛选，或者为了提供样本重复的测试，导致将双卵对错误地鉴定为单卵，对受访者关于合子问题的答案进行适当的分析至关重要。使用数据从一个年轻的成年澳大利亚双胞胎队列（N = 2094完整的对和519单胎双胞胎从同性对完整的反应，所有的卵性项目），我们表明，应用潜在的类分析（LCA），拟合2类模型，产生的结果显示良好的一致性与传统的方法的卵性诊断，但具有一定的重要优势。这些能力包括，在许多情况下，分配接合性与指定的概率的基础上，一个单一的信息（有利的是，当一个接合性类型被过度采样）的反应;和量化的接合性的误分配的概率，允许优先的情况下，基因分型以及鉴定的情况下，可能的实验室错误的能力。在242对双胞胎（来自121对同性对）中，基因型数据可用于接合性确认，只有一个案例被确定为不正确的接合性分配的潜在类算法。LCA将该单个病例的合子分配确定为不确定（单卵双胞胎的概率仅为76%），而共同双胞胎的反应明确将该对确定为双卵（双卵概率为100%）。在缺乏基因型数据的情况下，或者为了防止样本重复，强烈建议应用LCA进行接合性分配或确认。
For zygosity diagnosis in the absence of genotypic data, or in the recruitment phase of a twin study where only single twins from same-sex pairs are being screened, or to provide a test for sample duplication leading to the false identification of a dizygotic pair as monozygotic, the appropriate analysis of respondents' answers to questions about zygosity is critical. Using data from a young adult Australian twin cohort (N = 2094 complete pairs and 519 singleton twins from same-sex pairs with complete responses to all zygosity items), we show that application of latent class analysis (LCA), fitting a 2-class model, yields results that show good concordance with traditional methods of zygosity diagnosis, but with certain important advantages. These include the ability, in many cases, to assign zygosity with specified probability on the basis of responses of a single informant (advantageous when one zygosity type is being oversampled); and the ability to quantify the probability of misassignment of zygosity, allowing prioritization of cases for genotyping as well as identification of cases of probable laboratory error. Out of 242 twins (from 121 like-sex pairs) where genotypic data were available for zygosity confirmation, only a single case was identified of incorrect zygosity assignment by the latent class algorithm. Zygosity assignment for that single case was identified by the LCA as uncertain (probability of being a monozygotic twin only 76%), and the co-twin's responses clearly identified the pair as dizygotic (probability of being dizygotic 100%). In the absence of genotypic data, or as a safeguard against sample duplication, application of LCA for zygosity assignment or confirmation is strongly recommended.