Prader-Willi syndrome (PWS) is characterized by: hypotonia, failure to thrive in infancy, rapid weight gain/obesity between 12 months and 6 years, characteristic facial features, hypogonadism and mild to moderate mental retardation. Indications for testing include clinical characteristics of PWS or pregnancies at risk due to a known translocation or imprinting mutation.
Angelman syndrome (AS) is characterized by severe developmental delay/mental retardation, absence of speech, ataxic gait, inappropriate laughter, hand-flapping, and less frequently, microcephaly and seizures. Indications for testing include: clinical characteristics of AS or pregnancies at risk due to a known translocation or imprinting mutation. AS is not usually suspected in the first year of life, but becomes a consideration between 1-4 years of age.
Specimen Requirements:
Please Note: Call a laboratory genetic coordinator prior to obtaining specimens.
Blood:
- ACD-A (yellow-top) or EDTA (lavender-top) tube.
- Adult: 20 ml whole blood.
- Child: 5-7 ml whole blood.
AND
- Sodium heparin (green-top) tube.
- Adult: 5-10 ml whole blood.
- Child: 2-5 ml whole blood.
Turnaround Time:
2-4 weeks
Prader-Willi/Angelman Syndromes Protocol – Peripheral Blood Methylation Test
CPT Codes:
83891, 83892, 83894, 83912
Specimen Requirements:
Blood:
- ACD-A (yellow-top) or EDTA (lavender-top) tube.
- Adult: 20 ml whole blood.
- Child: 5-7 ml whole blood.
Turnaround Time:
2 weeks
Prader-Willi/Angelman Syndromes Protocol – Peripheral Blood Chromosome Analysis and FISH
CPT Codes:
88230(2), 88262, 88271(2), 88273(2), 88291(2)
Specimen Requirements:
Blood:
- Child: 2-5 ml in sodium heparin (green-top) tube.
- Adult: 5-10 ml in sodium heparin (green-top) tube.
Turnaround Time:
2 weeks
Prader-Willi/Angelman Syndromes Protocol – FISH (using slides or coverslips)
CPT Codes:
88271(2), 88273(2), 88291
Specimen Requirements:
If chromosome analysis has been performed previously, a fixed-cell pellet, or slides or coverslips, of fixed metaphase cell preparations may be sent for FISH analysis.
Turnaround Time:
2 weeks
Prader-Willi/Angelman Syndromes Protocol – Prenatal Chromosome Analysis and FISH (using prenatal specimens)
CPT Codes:
88230(2), 88262, 88271(2), 88273(2), 88291(2)
Specimen Requirements:
Please Note: Prior discussion and approval from the laboratory are required for all prenatal testing. Chorionic villi sampling is not suitable for prenatal testing using methylation for Prader-Willi/Angelman.
- If a specimen is sent for routine chromosome analysis, no additional specimen is required.
- Otherwise, send two T-25 flasks of confluent amniotic fluid cells or two T-25 flasks of chorionic villi cells.
Turnaround Time:
2 weeks (when cell culture required, add ~2 weeks)
Client Services:
Reproductive/Genetics
800-848-4436
Specimen Services/Pickup:
877-246-1226