UBE3A and Angelman syndrome: In Angelman syndrome, a severe and rare neurodevelopmental disorder, it has been reported that the lack of ubiquitin protein ligase E3A (UBE3A) expression leads to an increase in the Golgi pH, which in turn causes osmotic swelling of the Golgi cisternae with a concurrent reduction in protein sialylation, a process highly dependent on pH [30].