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Prader-Willi Syndrome
Clinical Genetic Test
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offered by
Genetics Laboratory
GTR Test Accession: Help GTR000500313.3
CAP
INHERITED DISEASEDYSMORPHOLOGYENDOCRINOLOGY ... View more
Last updated in GTR: 2023-02-08
View version history
Last annual review date for the lab: 2023-02-08 Past due LinkOut
At a Glance
Test purpose: Help
Diagnosis
Conditions (1): Help
Prader-Willi syndrome
Chromosomal regions/ Mitochondria (1): Help
15q11.2-q13
Genes (1): Help
SNRPN (15q11.2)
Methods (3): Help
Cytogenetics - FISH-metaphase: FISH; ...
Target population: Help
This test confirms a diagnosis of Prader-Willi Syndrome in patients …
Clinical validity: Help
The most sensitive single approach to diagnosing PWS and AS …
Clinical utility: Help
Establish or confirm diagnosis
Ordering Information
Offered by: Help
Genetics Laboratory
View lab's website
Test short name: Help
PWS
Specimen Source: Help
  • Amniocytes
  • Amniotic fluid
  • Cell culture
  • Chorionic villi
  • Cord blood
  • Fetal blood
  • Fibroblasts
  • Fresh tissue
  • Frozen tissue
  • Isolated DNA
  • Peripheral (whole) blood
  • Product of conception (POC)
  • View specimen requirements
Who can order: Help
  • Health Care Provider
  • Licensed Physician
  • Nurse Practitioner
  • Physician Assistant
CPT codes: Help
**AMA CPT codes notice

Copyright: 2023 American Medical Association. All rights reserved.

Contact Policy: Help
Laboratory can only accept contact from health care providers. Patients/families are encouraged to discuss genetic testing options with their health care provider.
How to Order: Help
Samples should be submitted with the appropriate requisition form (DNA test request form, Cytogenetics test request form). Samples are received Monday through Saturday. For DNA testing blood should be collected in EDTA or ACD tubes. For cytogenetic/FISH analysis, blood should be collected in sodium heparin tubes. Cultured prenatal specimens are …
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Test service: Help
Clinical Testing/Confirmation of Mutations Identified Previously
Genetic counseling
Prenatal tesing
FISH Analysis
Drug Metabolism testing
Cytogenetics Analysis
Maternal Serum Screening
Uniparental Disomy (UPD) Testing
X-Chromosome Inactivation Studies
Test development: Help
Test developed by laboratory (no manufacturer test name)
Informed consent required: Help
Decline to answer
Pre-test genetic counseling required: Help
Decline to answer
Post-test genetic counseling required: Help
Decline to answer
Recommended fields not provided:
Test Order Code, Lab contact for this test, Test strategy
Conditions Help
Total conditions: 1
Condition/Phenotype Identifier
Test Targets
Chromosomal regions/Mitochondria Help
Total chromosomal regions/mitochondria: 1
Chromosomal region/Mitochondrion Associated condition
Genes Help
Total genes: 1
Gene Associated Condition Germline or Somatic Allele (Lab-provided) Variant in NCBI
Methodology
Total methods: 3
Method Category Help
Test method Help
Instrument
FISH-metaphase
FISH
Methylation analysis
Methylation-specific PCR
BioRad CFX96
SeqStudio Genetic Analyzer
BioRad CFX96
SeqStudio Genetic Analyzer
Uniparental disomy study (UPD)
SNP Detection
Infinium Global Diversity Array with Enhanced PGx-8
Clinical Information
Test purpose: Help
Diagnosis
Clinical validity: Help
The most sensitive single approach to diagnosing PWS and AS is to study methylation patterns within 15q11-q13 using molecular genetic techniques. These will detect deletions, UPD and imprinting defects by establishing either a solely maternal methylated imprint (PWS) or paternal methylated imprint (AS).
View citations (1)
  • Ramsden SC, Clayton-Smith J, Birch R, Buiting K. Practice guidelines for the molecular analysis of Prader-Willi and Angelman syndromes. BMC Med Genet. 2010;11:70. doi:10.1186/1471-2350-11-70. Epub 2010 May 11. PMID: 20459762.
Clinical utility: Help
Establish or confirm diagnosis
View citations (1)
  • Jaeken J, Lefeber D, Matthijs G. Clinical utility gene card for: Phosphomannose isomerase deficiency. Eur J Hum Genet. 2014;22(9). doi:10.1038/ejhg.2014.29. Epub 2014 Feb 26. PMID: 24569608.

Target population: Help
This test confirms a diagnosis of Prader-Willi Syndrome in patients with clinical indications of PWS. Prenatal analysis may be appropriate for IVF pregnancies, individuals with a family history, or to confirm abnormal NIPT results.
View citations (3)
  • Cox GF, Bürger J, Lip V, Mau UA, Sperling K, Wu BL, Horsthemke B. Intracytoplasmic sperm injection may increase the risk of imprinting defects. Am J Hum Genet. 2002;71(1):162-4. doi:10.1086/341096. Epub 2002 May 08. PMID: 12016591.
  • Another case of imprinting defect in a girl with Angelman syndrome who was conceived by intracytoplasmic semen injection. Ørstavik KH, et al. Am J Hum Genet. 2003;72(1):218-9. doi:10.1086/346030. PMID: 12549484.
  • Ramsden SC, Clayton-Smith J, Birch R, Buiting K. Practice guidelines for the molecular analysis of Prader-Willi and Angelman syndromes. BMC Med Genet. 2010;11:70. doi:10.1186/1471-2350-11-70. Epub 2010 May 11. PMID: 20459762.
Recommended fields not provided:
What is the protocol for interpreting a variation as a VUS?, Are family members with defined clinical status recruited to assess significance of VUS without charge?, Will the lab re-contact the ordering physician if variant interpretation changes?, Is research allowed on the sample after clinical testing is complete?, Sample negative report, Sample positive report
Technical Information
Test Procedure: Help
Positive results are confirmed by comparison with known positive controls
Test Confirmation: Help
Positive results are confirmed by comparison with known positive controls
Availability: Help
Tests performed
Entire test performed in-house
Analytical Validity: Help
DNA-based methylation testing to detect abnormal parent-specific methylation within the PWS and AS critical region will detect more than 99% of individuals with PWS and approximately 80% of individuals with AS.
View citations (1)
  • Ramsden SC, Clayton-Smith J, Birch R, Buiting K. Practice guidelines for the molecular analysis of Prader-Willi and Angelman syndromes. BMC Med Genet. 2010;11:70. doi:10.1186/1471-2350-11-70. Epub 2010 May 11. PMID: 20459762.
Proficiency testing (PT):
Is proficiency testing performed for this test? Help
Yes

Method used for proficiency testing: Help
Formal PT program

PT Provider: Help
American College of Medical Genetics / College of American Pathologists, ACMG/CAP
Recommended fields not provided:
Assay limitations, Description of internal test validation method, Description of PT method, Major CAP category, CAP category, CAP test list
Regulatory Approval
FDA Review: Help
Category: FDA exercises enforcement discretion
Additional Information

IMPORTANT NOTE: NIH does not independently verify information submitted to GTR; it relies on submitters to provide information that is accurate and not misleading. NIH makes no endorsements of tests or laboratories listed in GTR. GTR is not a substitute for medical advice. Patients and consumers with specific questions about a genetic test should contact a health care provider or a genetics professional.