Descriptive Analysis of Adaptive Behavior in Phelan–McDermid Syndrome and Autism Spectrum Disorder

INTRODUCTION: The variety in symptomatology and clinical presentation of individuals diagnosed with Phelan-McDermid Syndrome (PMS) can delay medical diagnosis, so identifying specific neurobehavioral variables and facilitating differential diagnosis with patients with idiopathic Autism Spectrum Disorder (ASD) can guide early detection. METHODS: A descriptive analysis of the level of adaptive behavior in 50 patients diagnosed with PMS was performed (SHANK3(deletion): N = 44; SHANK(mutation): N = 6). Subsequently, a comparative analysis was performed with 28 children aged between 4 years and 6 years and 11 months (SHANK3(deletion) = 14; ASD = 14). Differences between the two groups were evaluated and Bonferroni correction was applied for multiple comparisons. RESULTS: Differences were identified in the variables of communication (z = −2.715, p = 0.007), Self-Direction (z = −2.199, p = 0.028) and social participation (z = −3.190, p = 0.001), with better adaptive behavior skills being observed in participants with a SHANK3(mutation). Better adaptive skills in the sample of participants with (ASD), were found and statistically significant differences were identified in the variables of academic skills (z = −3.084, p = 0.002), use of community resources (z = −1.889, p = 0.050) and health and safety (z = −2.90, p = 0.004). CONCLUSION: Participants with SHANK3(mutation) show better communication and social participation skills than those with a diagnosis of SHANK3(deletion). The observed differences between ASD and individuals with PMS reflect deficits in practical and conceptual adaptive skills that may limit and hinder daily adaptive functioning.