Center for Autism and Related Disorders, Kennedy Krieger Institute, Psychiatry and Behavioral Sciences, The Johns Hopkins University School of Medicine, Baltimore, MD 21211, USA.
J Child Psychol Psychiatry. 2012 Sep;53(9):986-96. doi: 10.1111/j.1469-7610.2012.02558.x. Epub 2012 May 10.
Siblings of children with autism (sibs-A) are at increased genetic risk for autism spectrum disorders (ASD) and milder impairments. To elucidate diversity and contour of early developmental trajectories exhibited by sibs-A, regardless of diagnostic classification, latent class modeling was used.
Sibs-A (N = 204) were assessed with the Mullen Scales of Early Learning from age 6 to 36 months. Mullen T scores served as dependent variables. Outcome classifications at age 36 months included: ASD (N = 52); non-ASD social/communication delay (broader autism phenotype; BAP; N = 31); and unaffected (N = 121). Child-specific patterns of performance were studied using latent class growth analysis. Latent class membership was then related to diagnostic outcome through estimation of within-class proportions of children assigned to each diagnostic classification.
A 4-class model was favored. Class 1 represented accelerated development and consisted of 25.7% of the sample, primarily unaffected children. Class 2 (40.0% of the sample), was characterized by normative development with above-average nonverbal cognitive outcome. Class 3 (22.3% of the sample) was characterized by receptive language, and gross and fine motor delay. Class 4 (12.0% of the sample), was characterized by widespread delayed skill acquisition, reflected by declining trajectories. Children with an outcome diagnosis of ASD were spread across Classes 2, 3, and 4.
Results support a category of ASD that involves slowing in early non-social development. Receptive language and motor development is vulnerable to early delay in sibs-A with and without ASD outcomes. Non-ASD sibs-A are largely distributed across classes depicting average or accelerated development. Developmental trajectories of motor, language, and cognition appear independent of communication and social delays in non-ASD sibs-A.
自闭症儿童的兄弟姐妹（sibs-A）患自闭症谱系障碍（ASD）和轻度障碍的遗传风险增加。为了阐明 sibs-A 所表现出的早期发育轨迹的多样性和轮廓，无论诊断分类如何，都使用潜在类别建模。
从 6 到 36 个月的年龄，使用 Mullen 早期学习量表对 sibs-A（N=204）进行评估。Mullen T 分数作为因变量。36 个月时的结果分类包括：ASD（N=52）；非 ASD 社交/沟通延迟（广泛自闭症表型；BAP；N=31）；和未受影响（N=121）。使用潜在类别增长分析研究儿童特定的表现模式。然后，通过估计每个诊断分类中分配给每个诊断分类的儿童的比例，将潜在类别成员与诊断结果相关联。
一个 4 类模型是有利的。类 1 代表加速发展，占样本的 25.7%，主要是未受影响的儿童。类 2（样本的 40.0%）的特点是正常发展，具有高于平均水平的非语言认知结果。类 3（样本的 22.3%）的特点是接受性语言以及粗大和精细运动延迟。类 4（样本的 12.0%）的特点是广泛的技能获取延迟，表现为下降轨迹。具有 ASD 结果诊断的儿童分布在 2、3 和 4 类中。
结果支持一种涉及早期非社交发展迟缓的 ASD 类别。接受性语言和运动发育在 ASD 和非 ASD 结果的 sibs-A 中容易出现早期延迟。非 ASD 的 sibs-A 主要分布在描绘平均或加速发展的各个类别中。在非 ASD 的 sibs-A 中，运动、语言和认知的发展轨迹与沟通和社会延迟无关。
