Uniparental disomy

Uniparental disomy is a factor that influences how some genetic conditions are inherited. 

Uniparental disomy (UPD) occurs when a person receives two copies of a chromosome, or part of a chromosome, from one parent and no copies from the other parent. UPD can occur as a random event during the formation of egg or sperm cells or may happen in early fetal development. 

G. Uniparental disomy refers to a condition in which one or more cells of the body have two identical chromosomes derived from a single parent, which increases the likelihood of expression of recessive alleles inherited from that parent. 

Uniparental disomy may contribute to BWS in that excess paternal or decreased maternal contributions of chromosome 11 have been observed in some patients. 

Uniparental disomy 7% (paternal) 25%-30% (maternal) Abnormal PCR for microsatellite... 

Both FISH and PCR-based detection of LOH can be achieved successfully in FFPE samples, and each method has its own limitations. FISH will show a false-negative result in the event of uniparental disomy (i.e., when cancer cells have lost one chromosome in the presence of duplication of another chromosomal allele). The PCR-based LOH analysis can detect the Ip loss in this situation. However, for optimal performance, the PCR-LOH analysis requires normal cells (isolated from normal tissue or blood) and must rely on amplification of several markers located in the same region because some of the microsatellite loci will be non-informative. 

Mostly sporadic (50-60% epigenetic imprinting defects), 15% AD with variable expressivity (130650) (CDKNlC)y 1-3% paternal duplication of llpl5, 20% uniparental disomy of llpl5... 

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