Prader‑Willi/Angelman Syndrome, DNA Methylation Analysis
Use
This assay aids in the diagnosis of Prader‑Willi syndrome and Angelman syndrome by detecting aberrant DNA methylation patterns in chromosome 15q11‑q13, encompassing abnormalities due to deletions, uniparental disomy (UPD), or imprinting defects. It can confirm over 99% of Prader‑Willi cases and approximately 80% of Angelman syndrome cases, serving as a definitive diagnostic tool when FISH results are normal or inconclusive. ([questdiagnostics.com](https://www.questdiagnostics.com/healthcare-professionals/clinical-education-center/faq/pwsfish?utm_source=openai))
Special Instructions
Performed by Quest Diagnostics Nichols Institute San Juan Capistrano. No prior or post‑test genetic counseling is explicitly required according to GTR information (state law may apply to consent). Insurance authorization may be required for outpatient collections. ([rchsd.org](https://www.rchsd.org/lab-test/prader-willi-angelman-syndrome-dna-methylation-analysis-11369/?utm_source=openai))
Limitations
This methylation‑specific PCR approach detects methylation abnormalities but cannot distinguish between deletion, uniparental disomy, or imprinting defect; further testing (e.g., FISH or CMA) may be needed for etiologic clarification. It does not detect mosaicism. ([ncbi.xyz](https://www.ncbi.xyz/gtr/tests/590570/?utm_source=openai))
New York Approved
Methodology
PCR-based (PCR)
Biomarkers
Result Turnaround Time
7 days
Related Documents
For more information, please review the documents below
Specimen
Whole Blood
Volume
3‑5 mL (1 mL for infants)
Minimum Volume
3 mL (1 mL for infants)
Container
Lavender (EDTA) tube; sodium heparin (green‑top) or ACD solution B (yellow‑top) tube also acceptable
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 8 Days |
| Refrigerated | 8 Days |
| Frozen | Unacceptable |
Other tests from different labs that may be relevant