Functional Analysis of Phenotypic Behaviors of a 5-Year-Old Male with Novel 4q21 Microdeletion

The 4q21 microdeletion syndrome is a relatively newer syndrome that has been recently characterized by mild to severe intellectual disability, growth delay, and behavioral problems. The literature reports that aggression and self-injurious behavior have been identified as elements of the 4q21 microdeletion behavioral phenotype (Bonnet et al. in Journal of Medical Genetics, 47, 377–384, 2010; Strehle et al. in American Journal of Medical Genetics Part A, 158A, 2139–2151, 2012; Tsang et al. in American Journal of Medical Genetics Part A, 158A, 2606–2609, 2012). In this case report, functional assessment of aggression and self-injurious behavior of a 5-year-old male with 4q21 microdeletion syndrome was completed to determine the function of behavior and evaluate the effectiveness of behavioral intervention. The assessment result informed treatment subsequently produced a decrease in the occurrence of problem behaviors. This is one of the first functional assessments completed on behaviors associated with 4q21 microdeletion. Furthermore, this study exemplifies the utility of functional assessments in assessing and treating behaviors in those with known genetic conditions.