Twin studies yield valuable insights into the sources of variation, covariation and causation in human traits. The ABCD Study® (abcdstudy.org) was designed to take advantage of four universities known for their twin research, neuroimaging, population-based sampling, and expertise in genetic epidemiology so that representative twin studies could be performed. In this paper we use the twin data to: (i) provide initial estimates of heritability for the wide range of phenotypes assessed in the ABCD Study using a consistent direct variance estimation approach, assuring that both data and methodology are sound; and (ii) provide an online resource for researchers that can serve as a reference point for future behavior genetic studies of this publicly available dataset. Data were analyzed from 772 pairs of twins aged 9–10 years at study inception, with zygosity determined using genotypic data, recruited and assessed at four twin hub sites. The online tool provides twin correlations and both standardized and unstandardized estimates of additive genetic, and environmental variation for 14,500 continuously distributed phenotypic features, including: structural and functional neuroimaging, neurocognition, personality, psychopathology, substance use propensity, physical, and environmental trait variables. The estimates were obtained using an unconstrained variance approach, so they can be incorporated directly into meta-analyses without upwardly biasing aggregate estimates. The results indicated broad consistency with prior literature where available and provided novel estimates for phenotypes without prior twin studies or those assessed at different ages. Effects of site, self-identified race/ethnicity, age and sex were statistically controlled. Results from genetic modeling of all 53,172 continuous variables, including 38,672 functional MRI variables, will be accessible via the user-friendly open-access web interface we have established, and will be updated as new data are released from the ABCD Study. This paper provides an overview of the initial results from the twin study embedded within the ABCD Study, an introduction to the primary research domains in the ABCD study and twin methodology, and an evaluation of the initial findings with a focus on data quality and suitability for future behavior genetic studies using the ABCD dataset. The broad introductory material is provided in recognition of the multidisciplinary appeal of the ABCD Study. While this paper focuses on univariate analyses, we emphasize the opportunities for multivariate, developmental and causal analyses, as well as those evaluating heterogeneity by key moderators such as sex, demographic factors and genetic background.

双胞胎研究对人类特征的变异、协变和因果关系的来源产生了宝贵的见解。ABCD Study® (abcdstudy.org) 旨在利用四所以双胞胎研究、神经影像学、基于人群的抽样和遗传流行病学专业知识而闻名的大学，以便开展具有代表性的双胞胎研究。在本文中，我们使用双胞胎数据来：(i) 使用一致的直接方差估计方法，为 ABCD 研究中评估的广泛表型提供遗传力的初步估计，确保数据和方法都是可靠的；(ii) 为研究人员提供在线资源，可以作为该公开数据集未来行为遗传学研究的参考点。在研究开始时分析了 772 对年龄在 9-10 岁的双胞胎的数据，使用基因型数据确定合子性，在四个双中心站点招募和评估。该在线工具为 14,500 个连续分布的表型特征提供双胞胎相关性以及加性遗传和环境变异的标准化和非标准化估计，包括：结构和功能神经影像学、神经认知、人格、精神病理学、物质使用倾向、身体和环境特征变量。估计值是使用无约束方差方法获得的，因此可以将它们直接纳入元分析，而不会向上偏向总体估计值。结果表明与现有文献具有广泛的一致性，并提供了对表型的新估计，而无需先前的双胞胎研究或在不同年龄进行的评估。网站的影响，自我认定的种族/族裔、年龄和性别均受到统计控制。所有 53,172 个连续变量（包括 38,672 个功能性 MRI 变量）的遗传建模结果将可通过我们建立的用户友好的开放访问 Web 界面访问，并将随着 ABCD 研究发布新数据而更新。本文概述了 ABCD 研究中包含的双胞胎研究的初步结果，介绍了 ABCD 研究和双胞胎方法的主要研究领域，并评估了初步发现，重点是数据质量和适用性使用 ABCD 数据集进行未来行为遗传学研究。提供了广泛的介绍性材料，以表彰 ABCD 研究的多学科吸引力。虽然本文侧重于单变量分析，