During the process of meiosis, usually a single pair of chromosomes will have each member inherited from each parent. Sometimes there are situations where a pair of chromosomes will have each member come from just one parent and not the other. This is called uniparental disomy. Uniparental disomy, or UPD, can sometimes cause abnormalities to the individual it occurs in. Some of the syndromes that UPD causes are Prader-Willi syndrome (PWS), Angelman syndrome (AS), and Beckwith-Widemann Syndrome (BWS). These syndromes have a wide variety of characteristics including mental retardation, seizures, and asymmetric body growth. Uniparental disomy has also been discovered as an aid in some diseases, such as cancer and cystic fibrosis, based on similar
