Brief Report: Challenging Behaviors in Toddlers and Preschoolers with Angelman, Prader-Willi, and Williams Syndromes.

The data are cross-sectional and parent-reported, so they cannot show how these behavior profiles change over time or what causes them. All reports came from mothers, and internalizing behaviors may be harder for parents to rate than externalizing behaviors. The sample was small, especially within each syndrome, and genetic or medical records verified diagnoses for only a majority of children with syndromes. Some behaviors known in older children with these syndromes, such as anxiety in Williams syndrome and compulsive behaviors, sleep problems, or temper tantrums in Prader-Willi syndrome, may not have appeared yet. The CBCL clinical ranges were not developed for these syndromes, so borderline or clinical scores may not capture syndrome-specific patterns. Cognitive functioning was not measured, so differences between syndromes could partly reflect developmental delay or cognition rather than behavior alone.

The authors declared no conflict of interest. The supplied text does not report funding.

Do not use the Child Behavior Checklist scores as syndrome-specific clinical thresholds. The paper says many challenging behaviors were below clinical ranges and clinical norms have not been developed for Angelman, Prader-Willi, or Williams syndrome.