Characteristics of Prader-Willi Syndrome and Early-onset Morbid Obesity

Prader-Willi syndrome (PWS) is a rare genetic disorder that affects about 1 in 14,000 people in the United States. As the most commonly identified genetic cause of obesity, PWS is often confused with Early-onset Morbid Obesity (EMO). Individuals with EMO show some signs of PWS, but clinically do not have PWS. The purpose of this study is to evaluate the clinical features and genetic basis of PWS and EMO, and to determine how these conditions affect a person throughout a lifetime.

PWS is a complex neurobehavioral syndrome. Clinical features include obesity, increased appetite, low muscle tone, cognitive impairment, distinct behavioral features, hypogonadism, and neonatal failure-to-thrive. It is the most commonly recognized genetic cause of obesity; however, many obese children do not in fact have PWS. These individuals are therefore diagnosed with EMO, a condition that shares features with PWS. The development of new advances and strategies for treating PWS and EMO requires a thorough understanding of the conditions at both the clinical and molecular levels. One goal of this study is to collect long-term data on individuals with PWS and EMO in order to gain a better understanding of the natural progression of the conditions, from the neonatal period well into adulthood. Specific to PWS, this study will establish a genotype-phenotype correlation among the different sub-types and will evaluate the effects of growth hormone treatment on disease progression. Lastly, the study will compare PWS with EMO in terms of clinical features and genetic basis.

Participation in this natural history study will entail an initial evaluation, followed by yearly study visits until the age of 3 and then every 2 years thereafter. Each study visit will last between 3 and 4 hours, and will include a physical exam (including a DEXA scan to determine body composition), psychological testing, an interview with the study physician, and an evaluation of the participant's diet history. In addition, blood tests will be completed for genetic testing and photos will be taken to evaluate disease progression. Cognitive and behavioral assessments will also be conducted and will last between 10 and 30 minutes.

Individuals with Prader-Willi syndrome and Early-onset Morbid Obesity

• Prader-Willi Syndrome
• Obesity

• Other: Group 1
  Individuals with Prader-Willi syndrome. Monitoring every 6 months.
  Other Names:

  • Prader-Willi syndrome
  • PWS
• Other: Group 2
  Individuals with Early-onset Morbid Obesity.
  Other Name: PWS

• Group 1
  Individuals with Prader-Willi syndrome.
  Intervention: Other: Group 1
• Group 2
  Individuals with Early-onset Morbid Obesity
  Intervention: Other: Group 2

• Miller J, Kranzler J, Liu Y, Schmalfuss I, Theriaque DW, Shuster JJ, Hatfield A, Mueller OT, Goldstone AP, Sahoo T, Beaudet AL, Driscoll DJ. Neurocognitive findings in Prader-Willi syndrome and early-onset morbid obesity. J Pediatr. 2006 Aug;149(2):192-8.
• Miller JL, Couch JA, Schmalfuss I, He G, Liu Y, Driscoll DJ. Intracranial abnormalities detected by three-dimensional magnetic resonance imaging in Prader-Willi syndrome. Am J Med Genet A. 2007 Mar 1;143(5):476-83.
• Butler MG. Management of obesity in Prader-Willi syndrome. Nat Clin Pract Endocrinol Metab. 2006 Nov;2(11):592-3. No abstract available.
• Butler MG, Bittel DC, Kibiryeva N, Talebizadeh Z, Thompson T. Behavioral differences among subjects with Prader-Willi syndrome and type I or type II deletion and maternal disomy. Pediatrics. 2004 Mar;113(3 Pt 1):565-73.
• Dykens E, Shah B. Psychiatric disorders in Prader-Willi syndrome: epidemiology and management. CNS Drugs. 2003;17(3):167-78. Review.
• Goldstone AP. Prader-Willi syndrome: advances in genetics, pathophysiology and treatment. Trends Endocrinol Metab. 2004 Jan-Feb;15(1):12-20. Review.
• Miller J, Silverstein J, Shuster J, Driscoll DJ, Wagner M. Short-term effects of growth hormone on sleep abnormalities in Prader-Willi syndrome. J Clin Endocrinol Metab. 2006 Feb;91(2):413-7. Epub 2005 Nov 29.
• Shapira NA, Lessig MC, He AG, James GA, Driscoll DJ, Liu Y. Satiety dysfunction in Prader-Willi syndrome demonstrated by fMRI. J Neurol Neurosurg Psychiatry. 2005 Feb;76(2):260-2.
• Bittel DC, Butler MG. Prader-Willi syndrome: clinical genetics, cytogenetics and molecular biology. Expert Rev Mol Med. 2005 Jul 25;7(14):1-20.
• Holsen LM, Zarcone JR, Brooks WM, Butler MG, Thompson TI, Ahluwalia JS, Nollen NL, Savage CR. Neural mechanisms underlying hyperphagia in Prader-Willi syndrome. Obesity (Silver Spring). 2006 Jun;14(6):1028-37.
• Cassidy SB, Driscoll DJ. Prader-Willi syndrome. Eur J Hum Genet. 2008 Sep 10; [Epub ahead of print]

Inclusion Criteria:

• Individuals enrolling in the Prader-Willi syndrome group will have a confirmed diagnosis of Prader-Willi syndrome, as confirmed by molecular and cytogenetic testing
• Individuals enrolling in the Early-onset Morbid Obesity group will have a documented medical history of their weight exceeding 150% of the ideal body weight or a body mass index greater than 97% before the age of 4 years; they will also be under the age of 30 years.

Exclusion Criteria:

• Known genetic, chromosomal, or hormonal cause of cognitive impairment other than Prader-Willi syndrome

• Office of Rare Diseases (ORD)
• Rare Diseases Clinical Research Network
• Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD)