BACKGROUND Individuals with autism spectrum disorder (ASD) have social interaction deficits and difficulties in emotional regulation. The neural substrates for these socio-affective deficits are not yet clear, but one potential candidate is maldevelopment of the uncinate fasciculus (UF), a white matter tract thought to be involved in socio-affective processing. However, the developmental trajectory of the UF in young children with social interaction deficits has not been examined. The present study was designed to describe the developmental growth trajectory of the UF and the relationships between UF development and social deficits in ASD. METHODS Eigenvalues of the UF were measured by diffusion tensor imaging (DTI)-based tractography in 37 children with ASD and 27 matched 2-3-year-old subjects with developmental delay (DD) at baseline (time 1) and at 2-year follow-up (time 2). Growth rates of the UF were compared between groups and associations with social deficit scores according to the Autism Diagnostic Interview-Revised (ADI-R) analyzed by Pearson's correlations. RESULTS At time 1, axial diffusivity (AD) of the left UF was significantly larger in the ASD group than the DD group. At time 2, left UF fractional anisotropy (FA) was significantly higher and radial diffusivity (RD) significantly lower in the ASD group than the DD group. The rate of UF growth during this 2-year interval was faster in children with ASD than DD. Significant negative correlations were found between the rise in ADI-R social deficit measures and both right UF RD and left UF mean diffusivity (MD). CONCLUSIONS Young children with ASD demonstrate UF overgrowth during the 2-year development period between 2 and 3 and 4-5 years of age, and this white matter abnormality is directly associated with the progression of social deficits. TRIAL REGISTRATION World Health Organization class I registered international clinical trial platform, ChiCTR-ROC-17012877.

中文翻译：

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自闭症谱系障碍学龄前儿童的束状束发育异常和社会缺陷。

背景技术患有自闭症谱系障碍（ASD）的个体具有社交互动缺陷和情绪调节困难。这些社会情感障碍的神经底物尚不清楚，但潜在的候选者是束状束（UF）的发育不良，UF是一种白质束，被认为与社会情感加工有关。但是，尚未检查具有社交互动缺陷的幼儿中超滤的发展轨迹。本研究旨在描述超滤的发展轨迹以及超滤发展与ASD中社会赤字之间的关系。方法通过基于弥散张量成像（DTI）的体表测量法，对37名ASD儿童和27名相匹配的2-3岁的2－3岁患有发育迟缓（DD）的受试者在基线（时间1）和2岁时的UF进行了特征值测量。随访（时间2）。根据通过皮尔逊相关性分析的《自闭症诊断访谈修订版》（ADI-R），比较了具有社会赤字得分的群体和协会之间超滤的增长率。结果在时间1，ASD组左UF的轴向扩散率（AD）明显大于DD组。在时间2，与DD组相比，ASD组的左UF分数各向异性（FA）明显更高，径向扩散率（RD）明显更低。在这2年的时间间隔中，ASD儿童的UF生长速度快于DD。发现ADI-R社会赤字测度的上升与右UF RD和左UF平均扩散率（MD）之间存在显着的负相关。结论ASD幼儿在2至3至4-5岁的2年发育期间表现出超滤过度，这种白质异常与社会缺陷的发展直接相关。试验注册世界卫生组织I类注册的国际临床试验平台ChiCTR-ROC-17012877。