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Published on: December 24, 2013
Parent-reported measure of repetitive behavior in Phelan-McDermid syndrome
Siddharth Srivastava1, Emma Condy2, Erin Carmody3
1Department of Neurology, Rosamund Stone Zander Translational Neuroscience Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA. siddharth.srivastava@childrens.harvard.edu.
Insights
Phelan McDermid syndrome (PMS) is a neurogenetic condition. Repetitive behaviors in PMS appear milder than in autism spectrum disorder (ASD) and may correlate with cognitive functioning.
Area of Science:
- Neurogenetics
- Behavioral Science
- Developmental Pediatrics
Background:
- Phelan McDermid syndrome (PMS) is a neurogenetic disorder.
- It is frequently associated with intellectual disability (ID) and autism spectrum disorder (ASD).
- Repetitive behaviors are a common feature, but their characteristics in PMS require further elucidation.
Purpose of the Study:
- To provide a comprehensive, quantitative profile of repetitive behaviors in individuals with Phelan McDermid syndrome.
- To explore the relationship between repetitive behaviors and intellectual functioning within this cohort.
Main Methods:
- A multicenter observational study included 90 individuals (age 3-21) with confirmed PMS diagnosis.
- Repetitive behaviors were assessed using the Repetitive Behavior Scales-Revised (RBS-R).
- Statistical analyses examined correlations between IQ and RBS-R scores.
Main Results:
- The mean IQ of the cohort was 26.08 ± 17.67, with varying degrees of ID.
- The overall RBS-R score (16.46 ± 13.9) was lower than previously reported for ASD cohorts.
- IQ significantly correlated with stereotypic behavior scores on the RBS-R (adjusted p = 0.01).
Conclusions:
- Repetitive behaviors in Phelan McDermid syndrome appear less severe than in autism spectrum disorder.
- Stereotypic behaviors in PMS may be linked to cognitive abilities and intellectual functioning.
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 (rs = - 0.33, unadjusted p = 0.0014, adjusted p = 0.01) and RBS-R stereotypic behavior total number of endorsed items (rs = - 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.
