To examine brain volumes in substructures associated with the behavioral features of children with FXS compared to children with idiopathic autism and controls. A cross-sectional study of brain substructures was conducted at the first time-point as part of an ongoing longitudinal MRI study of brain development in FXS. The study included 52 boys between 18-42 months of age with FXS and 118 comparison children (boys with autism-non FXS, developmental-delay, and typical development). Children with FXS and autistic disorder had substantially enlarged caudate volume and smaller amygdala volume; whereas those children with autistic disorder without FXS (i.e., idiopathic autism) had only modest enlargement in their caudate nucleus volumes but more robust enlargement of their amygdala volumes. Although we observed this double dissociation among selected brain volumes, no significant differences in severity of autistic behavior between these groups were observed. This study offers a unique examination of early brain development in two disorders, FXS and idiopathic autism, with overlapping behavioral features, but two distinct patterns of brain morphology. We observed that despite almost a third of our FXS sample meeting criteria for autism, the profile of brain volume differences for children with FXS and autism differed from those with idiopathic autism. These findings underscore the importance of addressing heterogeneity in studies of autistic behavior.

中文翻译：

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梳理自闭症的异质性：患有脆性 X 综合征和自闭症的幼儿具有相同的行为，不同的大脑。


与特发性自闭症儿童和对照组儿童相比，检查与 FXS 儿童行为特征相关的子结构中的脑容量。作为正在进行的 FXS 大脑发育纵向 MRI 研究的一部分，在第一个时间点进行了大脑亚结构的横断面研究。该研究包括 52 名 18-42 个月大的 FXS 男孩和 118 名对照儿童（患有自闭症但非 FXS、发育迟缓和典型发育的男孩）。患有 FXS 和自闭症的儿童尾状核体积显着增大，杏仁核体积较小；而那些没有 F​​XS 的自闭症儿童（即特发性自闭症），其尾状核体积仅适度增大，但其杏仁核体积却有更强烈的增大。尽管我们观察到选定脑容量之间的这种双重分离，但没有观察到这些组之间自闭症行为严重程度的显着差异。这项研究对 FXS 和特发性自闭症这两种疾病的早期大脑发育进行了独特的检查，它们具有重叠的行为特征，但大脑形态有两种不同的模式。我们观察到，尽管我们的 FXS 样本中有近三分之一符合自闭症标准，但 FXS 和自闭症儿童的大脑体积差异与特发性自闭症儿童不同。这些发现强调了解决自闭症行为研究中异质性的重要性。