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Prader-Willi/Angelman Syndrome Methylation Molecular Analysis

Methylation-specific polymerase chain reaction studies for Prader-Willi syndrome and Angelman syndrome, DNA deletion and uniparental disomy studies for Prader-Willi and Angelman syndromes

Test Codes

EPIC: LAB7157, SOFT: GPWAG

Department

Cytogenetics

Instructions

Transport 5 mL of peripheral blood (Minimum: 30.0 mL). If the specimen will not be received at the testing laboratory within 48 hours of collection, transport refrigerated. Do not freeze the specimen.

Specimen Collection Criteria

Collect: 5.0 mL peripheral blood in a lavender top EDTA tube, (Minimum: 3.0 mL)
A copy of the requisition must be sent with the specimen.

Physician Office/Draw Specimen Preparation

Do not freeze specimen or centrifuge the specimen. Maintain specimens at room temperature (20-25°C or 68-77°F) prior to transport. For delays in transport (greater than 48 hours from the time of collection), refrigerate (2-8°C or 36-46°F).  

Preparation for Courier Transport

Transport: Whole blood at room temperature (20-26°C or 68-78.8°F) or refrigerated (2-8°C or 36-46°F). (Minimum: 3.0 mL)

Rejection Criteria

• Specimens arriving in the laboratory 4 days or more following the original collection date.
• Frozen specimens.
• This test will only be performed once in a lifetime.

In-Lab Processing

Do not freeze specimen. Maintain specimens at room temperature (20-25°C or 68-77°F) prior to transport. For delays in transport (greater than 48 hours from the time of collection), refrigerate (2-8°C or 36-46°F).  

Specimens are processed immediately upon delivery to the Cytogenetics Laboratory.

Storage

Specimen Stability for Testing:

Room Temperature (20-26°C or 68-78.8°F): 7 days
Refrigerated (2-8°C or 36-46°F): 7 days
Frozen (-20°C/-4°F or below): Unacceptable

Specimen Storage in Department Prior to Disposal:

Extracted DNA is stored for one year.

Laboratory

Royal Oak Cytogenetics Laboratory

Performed

Once a week
Results are available within 10-14 days of receipt in the laboratory.

Reference Range

Positive for Prader-Willi Syndrome or Angelman syndrome/Normal chromosome 15q11q13 methylation pattern. An interpretative report will be provided.

Test Methodology

Methylation-sensitive PCR analysis of the SNRPN gene.

Interpretation

Abnormal chromosome 15q11q13 (SNRPN gene) methylation pattern consistent with either Prader-Willi or Angelman syndrome.

Clinical Utility

This is a diagnostic test for Prader-Willi and Angelman syndromes by DNA analysis.

CPT Codes

81331. SNRPN/UBE3A (small nuclear ribonucleoprotein polypeptide and ubiquitin protein ligase E3A) Prader-Willi-syndrome and/or Angelman syndrome methylation analysis.

Contacts

Last Updated

4/8/2024