Purpose This report aims to explore the diagnostic and clinical challenges associated with the co-occurrence of intellectual disability (ID), autism spectrum disorder (ASD) and attention-deficit/hyperactivity disorder (ADHD) in a patient with 16p11.2 duplication and significant psychosocial adversity. The case highlights the phenotypic heterogeneity of 16p11.2 duplication, the complexity of differential diagnosis in neurodevelopmental disorders and the interplay between genetic vulnerability and environmental factors in symptom presentation and treatment planning. Design/methodology/approach The case report details the patient’s history, presenting concerns, clinical findings and diagnostic assessments, including genetic testing (karyotype, array comparative genomic hybridization, quantitative polymerase chain reaction and multiplex ligation-dependent probe amplification) and psychopathological assessments. It outlines the proposed management plan, including methylphenidate sensitivity testing, a multidisciplinary approach and cautious psychopharmacology. Findings The patient exhibited delayed ambulation and language development, hyperactivity, poor sense of danger and impaired adaptive skills. He also showed anxiety, emotional and behavioral dyscontrol and school difficulties. Genetic testing confirmed a 16p11.2 duplication. Diagnoses included duplication of the short arm of chromosome 16, moderate ID, ASD and ADHD. Originality/value This report contributes to understanding the complex neurodevelopmental phenotype of 16p11.2 duplication, particularly by reporting for the first time the co-occurrence of ID, ASD and ADHD. It emphasizes challenges in differential diagnosis and the importance of considering genetic and environmental factors in clinical presentation.
Bertelli et al. (Thu,) studied this question.