How is Prader-Willi syndrome (PWS) diagnosed?

Updated: Oct 14, 2020
  • Author: Ann Scheimann, MD, MBA; Chief Editor: Luis O Rohena, MD, MS, FAAP, FACMG  more...
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Genetic testing for Prader-Willi syndrome includes chromosomal or microarray analysis and assessment for methylation patterns in the Prader-Willi syndrome region.

Fasting measurements of serum insulinlike growth factor-1 (IGF-1) and insulinlike growth factor binding protein-3 (IGFBP-3) levels are good screening measurements for underlying growth hormone deficiency. Refer patients with diminished growth velocity and abnormal levels of IGF-1 and IGFBP-3 to a pediatric endocrinologist for provocative growth hormone stimulation testing.

Assess thyroid and adrenal status in patients when clinically warranted.

Measure glycosylated hemoglobin in patients with Prader-Willi syndrome who are obese to assess for the development of type 2 diabetes mellitus as clinically warranted, especially if the patient is taking growth hormone supplementation.

Patients with Prader-Willi syndrome may require the following imaging studies: [6]

  • Magnetic resonance imaging (MRI) of the head (to evaluate for hypopituitarism)
  • Serial dual energy x-ray absorptiometry (DEXA) scanning (for detection and monitoring of osteoporosis) [7]
  • Scoliosis films
  • Chest radiography (if cor pulmonale is suspected)
  • Other imaging modalities as clinically dictated (eg, extremity film for limp evaluation, hip films to screen for hip dysplasia [8] )

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