Prader-Willi syndrome

Definition of Prader-Willi syndrome

Prader-Willi syndrome is a congenital (present from birth) disease that involves obesity, decreased muscle tone, decreased mental capacity, and sex glands that produce little or no hormones.

Causes, incidence, and risk factors

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 patients with Prader-Willi syndrome are missing the genetic material on part of the father’s chromosome. The remaining patients frequently have two copies of the mother’s chromosome 15.

Symptoms

Symptoms may include:

Signs and tests

Signs of Prader-Willi syndrome may be seen at birth. Newborns with the condition are often small and very floppy. Male infants may have undescended testicles.

Treatment

Obesity represents the greatest problem to health. Limiting caloric intake will control the obesity but the family, neighbors, school, and other institutions must cooperate closely as the child will attempt to obtain food wherever possible. Exercise can increase lean body mass in children with Prader-Willi syndrome.

Expectations (prognosis)

Appropriate education will be needed for the affected person’s IQ level. Weight control will allow for a much more comfortable and healthful life.

Review

Neil K. Kaneshiro, MD, MHA, Clinical Assistant Professor of Pediatrics, University of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc. – 11/2/2009

ADAM Medical Encyclopedia

Article written by

A.D.A.M., Inc. is accredited by URAC, also known as the American Accreditation HealthCare Commission (www.urac.org). URAC's accreditation program is an independent audit to verify that A.D.A.M. follows rigorous standards of quality and accountability.