Pregnancies at risk due to a known translocation or imprinting mutation. Pregnancies at low risk where added reassurance is indicated. 5 Patients with PWS have only a 4.2 kb band, patients with AS a 0.9 kb band. Positive individuals have a deletion at 15q11-13. Positive individuals exhibit markers corresponding to one or both homologs from a parent.
New insights reveal complex mechanisms involved in genomic imprinting.
Holm VA et al. Consensus diagnostic criteria. Consensus for diagnostic criteria. Buiting K et al. Inherited microdeletions in the Angelman and Prader-Willi syndromes define an imprinting center on human chromosome 15.