UBE3A (Ubiquitin Protein Ligase E3A): UBE3A is a gene that encodes an E3 ubiquitin ligase enzyme, which helps regulate protein degradation through the ubiquitin–proteasome pathway. It plays an important role in normal brain development and function. Mutations in UBE3A are linked to Angelman syndrome, a neurodevelopmental disorder marked by intellectual disability, developmental delay, and characteristic behavioral features.