Background and aims

Males with fragile X syndrome display many behavioral features of autism spectrum disorder. Despite this overlap, our understanding of autism spectrum disorder symptoms and severity in fragile X syndrome is limited due to variation in assessment methods in the literature. Furthermore, the relationship between autism spectrum disorder symptoms and child characteristics, like age, language, and cognitive abilities, are not well understood in individuals with fragile X syndrome. Therefore, the first research aim was to compare the rates of autism spectrum disorder classifications from three commonly reported autism spectrum disorder assessments in the literature. Our second research aim was to examine the relationship between autism spectrum disorder characteristics and other child characteristics.

Methods

The present study compared autism spectrum disorder classifications and symptoms using the Autism Diagnostic Observation Schedule, Autism Diagnostic Interview, Revised, and Childhood Autism Rating Scale, second edition in a sample of 33 school-age and adolescent boys with fragile X syndrome. In addition, the participants completed nonverbal IQ testing, expressive vocabulary and grammar tests, and a conversation language sample.

Results

The majority of the participants met criteria for autism spectrum disorder on the Autism Diagnostic Observation Schedule (96.97%) and Autism Diagnostic Interview, Revised (90.91%), while only half met criteria for autism spectrum disorder on the Childhood Autism Rating Scale, second edition. Sixteen boys (48.48%) met criteria for autism spectrum disorder on all three measures, and all participants met criteria for autism spectrum disorder on at least one measure. Expressive vocabulary accounted for a unique amount of variance in Childhood Autism Rating Scale, second edition and Autism Diagnostic Observation Schedule scores. Additionally, grammatical complexity accounted for a unique amount of variance in Childhood Autism Rating Scale, second edition scores. None of the child variables accounted for the variance found in Autism Diagnostic Interview, Revised scores. Although nonverbal IQ scores did not account for a significant amount of variance on the Autism Diagnostic Observation Schedule, Autism Diagnostic Interview, Revised, and Childhood Autism Rating Scale, Second Edition, boys who met criteria for autism spectrum disorder on all three measures had lower nonverbal IQ compared to the boys who did not. Additionally, mean length of utterance and expressive vocabulary scores were lower in the boys who met criteria for autism spectrum disorder on all three measures than those who did not.

Conclusions

Our findings identify areas of overlap and difference in the Autism Diagnostic Observation Schedule, Autism Diagnostic Interview, Revised, and Childhood Autism Rating Scale, second edition when used with males with fragile X syndrome. Variation in assessments may differentially identify the phenotypic behaviors of boys with fragile X syndrome that lead to a co-diagnosis of autism spectrum disorder, which contributes to the variation in reported co-morbidity of fragile X syndrome and autism spectrum disorder. Also, expressive language abilities, especially expressive vocabulary, are associated with autism spectrum disorder symptomatology.

Implications: When interpreting comorbid fragile X syndrome and autism spectrum disorder rates in the literature, it is important to consider the assessment tool that was used. Although the assessments that we used in the present study yielded scores that were highly correlated (i.e. Autism Diagnostic Observation Schedule and Childhood Autism Rating Scale, second edition), their categorical classifications did not align perfectly. Our findings also highlight the importance of considering language skills when assessing autism spectrum disorder severity in fragile X syndrome.

中文翻译：

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患有脆性 X 综合征的男孩同时发生自闭症谱系障碍的比率和预测因素

 背景和目标

患有脆性 X 综合征的男性表现出自闭症谱系障碍的许多行为特征。尽管存在这种重叠，但由于文献中评估方法的差异，我们对自闭症谱系障碍症状和脆性 X 综合征严重程度的理解仍然有限。此外，对于患有脆性 X 综合征的个体，自闭症谱系障碍症状与儿童特征（如年龄、语言和认知能力）之间的关系尚不清楚。因此，第一个研究目的是比较文献中三种常见报告的自闭症谱系障碍评估的自闭症谱系障碍分类率。我们的第二个研究目标是检查自闭症谱系障碍特征与其他儿童特征之间的关系。

 方法

本研究使用自闭症诊断观察表、自闭症诊断访谈修订版和儿童自闭症评定量表（第二版）对 33 名患有脆性 X 综合征的学龄和青春期男孩进行了样本比较，对自闭症谱系障碍的分类和症状进行了比较。此外，参与者还完成了非语言智商测试、表达词汇和语法测试以及会话语言样本。

 结果

大多数参与者符合自闭症诊断观察表（96.97%）和修订版自闭症诊断访谈（90.91%）中的自闭症谱系障碍标准，而只有一半的参与者符合第二版儿童自闭症评定量表中的自闭症谱系障碍标准。十六名男孩（48.48%）在所有三项指标上均符合自闭症谱系障碍标准，所有参与者至少在一项指标上符合自闭症谱系障碍标准。表达性词汇在儿童自闭症评定量表第二版和自闭症诊断观察表分数中造成了独特的差异。此外，语法复杂性导致了《儿童自闭症评定量表》第二版分数中独特的差异量。没有任何子变量能够解释自闭症诊断访谈修订分数中发现的方差。尽管非语言智商分数并不能解释自闭症诊断观察表、自闭症诊断访谈修订版和儿童自闭症评定量表第二版的显着差异，但在所有三项指标上均符合自闭症谱系障碍标准的男孩的非语言智商较低。与没有智商的男孩相比。此外，在所有三项指标上均符合自闭症谱系障碍标准的男孩的平均言语长度和表达词汇得分低于那些不符合自闭症谱系障碍标准的男孩。

 结论

我们的研究结果确定了自闭症诊断观察表、自闭症诊断访谈修订版和儿童自闭症评定量表第二版在用于患有脆性 X 综合征的男性时的重叠和差异领域。评估的差异可能会差异化地识别患有脆性 X 综合征的男孩的表型行为，从而导致对自闭症谱系障碍的共同诊断，从而导致报告的脆性 X 综合征和自闭症谱系障碍的共病情况发生变化。此外，表达语言能力，尤其是表达词汇，与自闭症谱系障碍的症状相关。

意义：在解释文献中的共病脆性 X 综合征和自闭症谱系障碍发生率时，重要的是要考虑所使用的评估工具。尽管我们在本研究中使用的评估产生了高度相关的分数（即自闭症诊断观察表和儿童自闭症评定量表，第二版），但它们的分类并没有完全一致。我们的研究结果还强调了在评估脆性 X 综合征的自闭症谱系障碍严重程度时考虑语言技能的重要性。