Prader Willi syndrome (PWS) is characterized by severe hypotonia, poor feeding in early infancy followed later in childhood by excessive eating that can lead to obesity. Children with PWS may present with delayed milestones/intellectual delay, strabismus, scoliosis, speech delay, delayed puberty, short stature, small hands and feet, insatiable appetite, hypogonadism, and mild-to-moderate mental retardation. PWS affects both genders equally and occurs in people from all geographic regions. Prader-Willi syndrome is due to a deletion of material from chromosome 15. The loss is consistently from the father's contribution of chromosome 15. A child with PWS will have two copies of chromosome region 15q11-13 but both will be from the mother.

This assay employs DNA methylation analysis of the Prader-Willi syndrome critical region and detects abnormalities in the parent-specific DNA methylation imprint in approximately 99% of individuals with Prader-Willi syndrome (PWS). It detects methylation abnormalities due to a deletion, uniparental disomy, or an imprinting defect and will also differentiate PWS from AS, when due to a deletion. The American Academy of Pediatrics (AAP) has stated that diagnostic testing for PWS should begin with methylation analysis to confirm the absence of paternally imprinted genes in the PWS region of chromosome 15.

CPT Code: 81331

Specimen Requirements: 2-5 mL Blood- EDTA tube (Lavender Top)

For Buccal Swab or Saliva samples please contact the lab to obtain a collection kit.

Turn-around-time: 21 days

Disease Specific DNA Test Order Form






Contact Information

OUHSC Genetics Laboratory 1122 NE 13th Street, Suite 1400, Oklahoma City, OK 73104

Phone (405)271-3589 Fax (405)271-7117 After hours phone (405)496-9514


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