Test Catalog

Test ID: PWAS    
Prader-Willi/Angelman Syndrome, Molecular Analysis, Varies

Useful For Suggests clinical disorders or settings where the test may be helpful

Confirmation of diagnosis in patients suspected of having either Prader-Willi syndrome (PWS) or Angelman syndrome (AS) based on clinical assessment or previous laboratory analysis


Prenatal diagnosis in families at risk for PWS or AS

Genetics Test Information Provides information that may help with selection of the correct genetic test or proper submission of the test request

Preferred first-tier test for diagnosis of Angelman syndrome (AS) and Prader-Willi syndrome (PWS). Multiplex ligation probe amplification (MLPA) is used to identify abnormal methylation of the PWS/AS region of chromosome 15.


Mayo Clinic Laboratories highly recommends that this test be ordered along with a routine chromosomal microarray analysis, CMACB / Chromosomal Microarray, Congenital, Blood, if the diagnosis of PWS or AS is not certain and chromosome analysis has not already been done.

Reflex Tests Lists tests that may or may not be performed, at an additional charge, depending on the result and interpretation of the initial tests.

Test IDReporting NameAvailable SeparatelyAlways Performed
CULAFAmniotic Fluid Culture/Genetic TestYesNo
MATCCMaternal Cell Contamination, BYesNo

Testing Algorithm Delineates situations when tests are added to the initial order. This includes reflex and additional tests.

For prenatal specimens only: If amniotic fluid (nonconfluent cultured cells) is received, amniotic fluid culture/genetic test will be added at an additional charge. For any prenatal specimen that is received, maternal cell contamination studies will be added.


See Prader-Willi and Angelman Syndromes: Laboratory Approach to Diagnosis in Special Instructions.

Special Instructions Library of PDFs including pertinent information and forms related to the test

Method Name A short description of the method used to perform the test

Methylation-Sensitive Multiple Ligation-Dependent Probe Amplification (MLPA)

NY State Available Indicates the status of NY State approval and if the test is orderable for NY State clients.


Reporting Name Lists a shorter or abbreviated version of the Published Name for a test

Prader Willi/Angelman Mol Analysis

Aliases Lists additional common names for a test, as an aid in searching

Angelman Syndrome, Uniparental Disomy and Deletions
Methylation Studies
Prader-Willi Syndrome, Uniparental Disomy and Deletions