Prader-Willi Syndrome (PWS)/Angelman Syndrome

Indications For Prader-Willi Syndrome (PWS) / Angelman Syndrome

Diagnostic criteria for PWS may include: hypotonia, failure to thrive, rapid weight gain between 12 months and 6 years, characteristic facial features, hypogonadism and mild to moderate mental retardation.  Diagnostic criteria for Angelman Syndrome may include feeding problems in the first few months of life, developmental delay, seizures, microcephaly, movement and balance disorders, hand-flapping, frequent outbursts of inappropriate laughter. 

Collection Procedure

  • Peripheral blood Collect whole blood in a green top tube (sodium heparin).  Label tube with patient’s name and date of birth.

A completed test requisition form must be included with every sample.  A transport kit is available upon request.

Specimen Requirements

FISH analysis is performed following cytogenetic analysis

Transport Temperature

Room temperature (DO NOT refrigerate, freeze or centrifuge)

Laboratory Testing for Prader-Willi Syndrome (PWS) / Angelman Syndrome is performed on metaphase chromosomes utilizing Fluorescence in situ hybridization targeting chromosome 15.

Causes for Rejection

Frozen specimen, inappropriate container

Turnaround Time

24-48 hrs after completion of cytogenetic analysis