Prader-Willi syndrome is a congenital (present from birth) disease. It affects many parts of the body. People with this condition are obese, have reduced muscle tone and mental ability, and have sex glands that produce little or no hormones.
Prader-Willi syndrome is caused by a gene missing on part of chromosome 15. Normally, your parents each pass down a copy of this chromosome. Most persons with Prader-Willi syndrome are missing the genetic material on part of the father's chromosome. The rest of persons with this condition often have two copies of the mother's chromosome 15.
The genetic changes occur randomly. Persons who have this syndrome usually do not have a family history of the condition.
Signs of Prader-Willi syndrome may be seen at birth.
Other symptoms may include:
Children have an intense craving for food and will do almost anything to get it. This can result in uncontrollable weight gain and morbid obesity. Morbid obesity may lead to type 2 diabetes, high blood pressure, and joint and lung problems.
Genetic testing is available to test children for Prader-Willi syndrome.
As the child grows older, laboratory tests may show signs of morbid obesity, such as:
There may also be signs of right-sided heart failure and knee and hip problems.
Obesity is the greatest threat to health. Limiting calories will control the obesity, but the family, neighbors, and school must work together closely because the child will try to get food wherever possible. Exercise can increase lean body mass in children with Prader-Willi syndrome.
Growth hormone is approved by the Food and Drug Administration for the treatment of Prader-Willi syndrome. It can help:
There have been some concerns that taking growth hormone therapy may lead to sleep apnea. A child who takes hormone therapy needs to have annual sleep studies to monitor for sleep apnea.
Low levels of sex hormones may be corrected at puberty with hormone replacement.
For additional resources and support, see:
The child will need the right education for his or her IQ level. The child will also need speech, physical, and occupational therapy as early as possible. Controlling weight will allow for a much more comfortable and healthy life.
Call your health care provider if your child has symptoms of this condition. The disorder is frequently suspected at birth.
Cooke DW, Divall SA, Radovick S. Normal and aberrant growth. In: Melmed S, ed. Williams Textbook of Endocrinology. 12th ed. Philadelphia, PA: Saunders Elsevier; 2011:chap 24.
Updated by: Neil K. Kaneshiro, MD, MHA, Clinical Assistant Professor of Pediatrics, University of Washington School of Medicine, Seattle, WA. Also reviewed by A.D.A.M. Health Solutions, Ebix, Inc., Editorial Team: David Zieve, MD, MHA, Bethanne Black, Stephanie Slon, and Nissi Wang.
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