On human chromosome 15q11-q13, several brain-specific genes are expressed exclusively from the paternally inherited allele and only two genes, Ube3a and Atp10a, are expressed from the maternally inherited allele (Chamberlain and Lalande, 2010); these paternally and maternally inherited genes are controlled by the Prader-Willi Syndrome (PWS) and Angelman Syndrome (AS) imprinting centers, respectively (Saitoh et al., 1996). The gene discussed is UBE3A; the disease is Prader-Willi syndrome.