Parent-reported measure of repetitive behavior in Phelan-McDermid syndrome
Siddharth Srivastava, Emma Condy, Erin Carmody, Rajna Filip‐Dhima, Kush Kapur, Jonathan A. Bernstein, Elizabeth Berry‐Kravis, Craig M. Powell, Latha Soorya, Audrey Thurm, Joseph D. Buxbaum, Mustafa Şahin, Alexander Kolevzon, Mustafa Şahin, Alexander Kolevzon, Joseph D. Buxbaum, Elizabeth Berry Kravis, Latha Soorya, Audrey Thurm, Craig M. Powell, Jonathan A. Bernstein, Simon K. Warfield, Kira A. Dies, Paige M. Siper, Ellen Hanson, Jennifer M. Phillips
Abstract
Abstract Background Phelan McDermid syndrome (PMS) is a neurogenetic condition associated with a high prevalence of intellectual disability (ID) and autism spectrum disorder (ASD). This study provides a more comprehensive and quantitative profile of repetitive behaviors within the context of ID seen with the condition. Methods Individuals age 3–21 years with a confirmed PMS diagnosis participated in a multicenter observational study evaluating the phenotype and natural history of the disorder. We evaluated data collected from this study pertaining to repetitive behaviors from the Repetitive Behavior Scales-Revised (RBS-R). Results There were n = 90 participants who were part of this analysis. Forty-seven percent ( n = 42/90) were female, and the average age at baseline evaluation was 8.88 ± 4.72 years. The mean best estimate IQ of the cohort was 26.08 ± 17.67 (range = 3.4–88), with n = 8 with mild ID (or no ID), n = 20 with moderate ID, and n = 62 with severe-profound ID. The RBS-R total overall score was 16.46 ± 13.9 (compared to 33.14 ± 20.60 reported in previous studies of ASD) (Lam and Aman, 2007), and the total number of items endorsed was 10.40 ± 6.81 (range = 0–29). After statistical correction for multiple comparisons, IQ correlated with the RBS-R stereotypic behavior subscale score ( r s = − 0.33, unadjusted p = 0.0014, adjusted p = 0.01) and RBS-R stereotypic behavior total number of endorsed items ( r s = − 0.32, unadjusted p = 0.0019, adjusted p = 0.01). IQ did not correlate with any other RBS-R subscale scores. Conclusions The RBS-R total overall score in a PMS cohort appears milder compared to individuals with ASD characterized in previous studies. Stereotypic behavior in PMS may reflect cognitive functioning.