Fang et al. (1999) sequenced the major coding exons of the UBE3A gene in 56 index patients with a clinical diagnosis of Angelman syndrome (105830) and a normal DNA methylation pattern. Disease-causing mutations were identified in 17 of the 56 patients (30%),
Matsuura and colleagues (1997) identified 4 truncating mutations in the ubiquitin protein ligase E3A (UBE3A) gene in patients with Angelman Syndrome (AS). AS is characterized by impaired motor and cognitive development, sleep disturbance, clumsy gait, seizures and irregular behaviors such as flapping and bursts of laughter. In mice, these features correlate with the loss of maternal-specific expression of Ube3a in the hippocampus and cerebellum. UBE3A has also been explored a possible candidate gene for autism and is supported by Nurni and colleagues (2001), but not by Veenstra-VanderWeele et al. (1999).