Angelman syndrome (AS) is a neurodevelopmental disorder caused by maternal deficiency of the UBE3A gene that encodes E6-AP ubiquitin-protein ligase. Expression of the UBE3A gene from the maternal chromosome is essential to prevent AS. AS is characterized by severe mental retardation, ataxia, and a defined behavioral pattern characterized mainly by happy/sociable disposition. This study used the Bayley Scales of Infant Development and the Vineland Adaptive Behavior Scales to examine the cognitive abilities and adaptive behavior of children (n = 20) with the four known molecular classes of AS, including patterns of strengths and weaknesses across adaptive behavior domains, and the relationship between adaptive behavior and overall cognitive abilities. Cognitive skills fell within the severe to profound range of mental deficiency. Differences in cognitive skills according to genetic subtype only partially supported previous research and suggest that there is overlap in abilities across genetic subtypes of AS. Adaptive behavior skills were also significantly delayed, with participants demonstrating a significant strength in socialization, and a weakness in motor skills. Strong, positive correlations emerge between cognitive ability scores and adaptive behaviors scores. These results provide further delineation of a cognitive/behavioral phenotype in AS.
Copyright 2004 Wiley-Liss, Inc.