BACKGROUND The neuroanatomical bases of autism spectrum disorder remain largely unknown. Among the most widely discussed candidate endophenotypes, differences in cerebellar volume have been often reported as statistically significant. METHODS We aimed at objectifying this possible alteration by performing a systematic meta-analysis of the literature and an analysis of the ABIDE (Autism Brain Imaging Data Exchange) cohort. Our meta-analysis sought to determine a combined effect size of autism spectrum disorder diagnosis on different measures of the cerebellar anatomy as well as the effect of possible factors of variability across studies. We then analyzed the cerebellar volume of 328 patients and 353 control subjects from the ABIDE project. RESULTS The meta-analysis of the literature suggested a weak but significant association between autism spectrum disorder diagnosis and increased cerebellar volume (p = .049, uncorrected), but the analysis of ABIDE did not show any relationship. The studies meta-analyzed were generally underpowered; however, the number of statistically significant findings was larger than expected. CONCLUSIONS Although we could not provide a conclusive explanation for this excess of significant findings, our analyses would suggest publication bias as a possible reason. Finally, age, sex, and IQ were important sources of cerebellar volume variability, although independent of autism diagnosis.

中文翻译：

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自闭症小脑体积：文献荟萃分析与自闭症脑成像数据交换队列分析

背景自闭症谱系障碍的神经解剖学基础在很大程度上仍是未知的。在最广泛讨论的候选内表型中，小脑体积的差异经常被报告为具有统计学意义。方法我们旨在通过对文献进行系统的荟萃分析和对 ABIDE（自闭症脑成像数据交换）队列的分析来客观化这种可能的改变。我们的荟萃分析试图确定自闭症谱系障碍诊断对小脑解剖学不同测量的综合影响大小，以及研究中可能的变异因素的影响。然后我们分析了来自 ABIDE 项目的 328 名患者和 353 名对照受试者的小脑体积。结果 文献荟萃分析表明，自闭症谱系障碍诊断与小脑体积增加之间存在微弱但显着的关联（p = .049，未校正），但对 ABIDE 的分析未显示任何关系。荟萃分析的研究总体上缺乏说服力；然而，具有统计意义的发现数量比预期的要多。结论 尽管我们无法对这种过多的重要发现提供结论性的解释，但我们的分析表明发表偏倚是一个可能的原因。最后，年龄、性别和智商是小脑体积变异性的重要来源，尽管与自闭症诊断无关。荟萃分析的研究总体上缺乏说服力；然而，具有统计意义的发现数量比预期的要多。结论 尽管我们无法对这种过多的重要发现提供结论性的解释，但我们的分析表明发表偏倚是一个可能的原因。最后，年龄、性别和智商是小脑体积变异性的重要来源，尽管与自闭症诊断无关。荟萃分析的研究总体上缺乏说服力；然而，具有统计意义的发现数量比预期的要多。结论 尽管我们无法对这种过多的重要发现提供结论性的解释，但我们的分析表明发表偏倚是一个可能的原因。最后，年龄、性别和智商是小脑体积变异性的重要来源，尽管与自闭症诊断无关。