PraderWilli Syndrome and Angelman Syndrome



PRADER-WILLI SYNDROME (PWS) and ANGELMAN SYNDROME (AS) are distinct neurogenetic disorders, both usually caused by chromosomal deletions on chromosome 15q11 or by uniparental disomy. The chromosomal alterations result in an aberrant expression profileof gene loci that are subject to imprinting. Absence of a paternal allele of chromosome 15q11, due to chromosomal deletion or uniparental disomy, results in PWS. The absence of the maternal copy of the same region causes AS.


This SALSA® MS-MLPA® probemix ME028 can be used to detect copy number changes, as well as to analyze CpG island methylation of the 15q11 region in a semi-quantitative manner. This SALSA® MLPA® ME028-B2 PWS/AS probemix contains 32 probes specific for sequences in or near the PWS/AS critical region of chromosome 15q11, which can be used to detect copy number changes in this region. Five of these probes are specific for an imprinted sequence and contain a recognition site for the methylation sensitive HhaI enzyme. These five probes can be used for the presence of aberrant methylation patterns in the 15q11 locus, either caused by uniparental disomy or by imprinting defects. For the analysis of results, 14 reference probes for genes located outside the PWS/AS region are present. In addition, three probes are present that will indicate complete digestion by the HhaI enzyme in the methylation quantification reaction.