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Prader-Willi / Angelman Syndrome

Test Information

Test Name: Prader-Willi / Angelman Syndrome

Performing Lab: Molecular Diagnostic

Synonyms: Angelman/P-W
Prader Willi Angelman Syndrome

Order Includes: Prader-Willi / Angelman Syndrome
P-W/Angleman Titer

Turnaround Time: 21 days

Additional Interpretation: Prader Willi (PWS) and Angelman Syndrome (AS) are two distinct clinical disorders caused by alterations in the same imprinted region of DNA on 15q11-q13. Deletion of the paternal allele or uniparental disomy of the maternal allele would be consistent with Prader Willi syndrome, while deletion of the maternal allele or uniparental disomy of the paternal allele would be consistent with Angelman syndrome. This test does not permit distinction between the two mechansims of a deletion and uniparental disomy, both of which have low recurrence risk (about 1% and 2%, respectively), nor an imprinting mutation, which is extremely rare. The presence of a deletion can often be confirmed by fluorescence in situ hybridization (FISH) using the SNRPN probe. If clinically indicated, additional studies such as FISH, comprehensive cytogenetic, or mutation analysis of the UAE3 gene for Angelman Syndrome should be considered.

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Methodology: Results are based upon polymerase chain reaction (PCR) amplification of DNA. DNA is treated with sodium bisulfite to allow detection of methylation within CpG islands. PCR using specific primers amplifies gene regions of interest including a wild type set, a methylated set, and an unmethylated set. Amplification by the methylated set alone is associated with Prader-Willi and by the unmethylated set alone with Angelman syndrome.

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CPT Code: 81331



Result Information

No Information Available



Specimen & Collection Information

Specimen Name: Whole Blood

Container Type: Lavender Top (EDTA)

Special Handling: Refrigerate

Specimen Volume: Lavender Top: 2.0 mL

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Specimen Transportation & Storage Information

Storage and Transport:Blood:
Deliver to the lab immediately. Remote Locations : Blood:
Do not spin. Store refrigerated at 2°C to 8°C.