Repetitive behaviors (RB) represent a wide spectrum of symptoms ranging from sensory-motor stereotypies to complex cognitive rituals, frequently dichotomized as low- and high-order sub-groups of symptoms. Even though these subgroups are considered as phenomenologically distinct in autism spectrum disorder (ASD) and obsessive–compulsive disorder (OCD), brain imaging and genetic studies suggest that they have common mechanisms and pathways. This discrepancy may be explained by the frequent intellectual disability reported in ASD, which blurs the RB expressivity. Given the high heritability of RB, that is, the diversity of symptoms expressed in the relatives are dependent on those expressed in their probands, we hypothesize that if RB expressed in ASD or OCD are two distinct entities, then the RB expressed in relatives will also reflect these two dimensions. We thus conduct a linear discriminant analysis on RB in both the relatives of probands with ASD and OCD and subjects from the general population (n = 1023). The discriminant analysis results in a classification of 81.1% of the controls (p < 10⁻⁴), but poorly differentiated the ASD and OCD relatives (≈46%). The stepwise analysis reveals that five symptoms attributed to high-order RB and two related to low-order RB (including hypersensitivity) are the most discriminant. Our results support the idea that the difference of RB patterns in the relatives is mild compared with the distribution of symptoms in controls. Our findings reinforce the evidence of a common biological pattern of RB both in ASD and OCD but with minor differences, specific to each of these two neuro-developmental disorders.

中文翻译：

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自闭症谱系障碍和强迫症先证者家庭重复行为的判别价值

重复行为 (RB) 代表了广泛的症状，从感觉运动刻板印象到复杂的认知仪式，经常被分为低级和高级症状亚组。尽管这些亚组在自闭症谱系障碍 (ASD) 和强迫症 (OCD) 中被认为在现象学上是不同的，但脑成像和遗传研究表明它们具有共同的机制和途径。这种差异可能是由于 ASD 中报告的频繁的智力障碍导致了 RB 表达能力的模糊。鉴于 RB 的高遗传性，即亲属中表达的症状的多样性取决于先证者中表达的症状，我们假设如果在 ASD 或 OCD 中表达的 RB 是两个不同的实体，那么亲戚中表达的RB也会反映这两个维度。因此，我们对患有 ASD 和 OCD 的先证者的亲属以及来自普通人群的受试者的 RB 进行了线性判别分析（n  = 1023）。判别分析导致 81.1% 的对照分类（p  < 10 ^-4），但 ASD 和 OCD 亲属的分类差（≈46%）。逐步分析显示，归因于高阶 RB 的五个症状和与低阶 RB 相关的两个症状（包括超敏反应）是最具辨别力的。我们的结果支持这样的观点，即与对照组的症状分布相比，亲属中 RB 模式的差异是轻微的。我们的研究结果加强了 ASD 和 OCD 中 RB 的共同生物学模式的证据，但略有不同，特定于这两种神经发育障碍中的每一种。