By Hugh C. McBride

Childhood obesity continues to be a prevalent problem in the United States and many other nations, and health experts have not been shy about pointing the finger at the culprits that contribute to this health dilemma.

When it comes to the causes of childhood obesity, the "usual suspects" include lack of physical education and recess, the rise of video-game culture, an over-indulgence on fast food and carbonated beverages, and an unwillingness of parents to establish and enforce common-sense health rules for their children.

What is not nearly so widely reported is that some cases of childhood obesity are the result of Prader-Willi Syndrome, a rare genetic disorder that affects about one of every 15,000 people. Though it is relatively unknown among the general public, Prader-Willi Syndrome has been recognized as the most common genetic cause of potentially life-threatening childhood obesity.

An Insatiable Hunger

Resulting from an abnormality on the 15 chromosome, Prader-Willi Syndrome manifests with a variety of physical and developmental symptoms, including (as described on the website of the Prader-Willi Syndrome Association) "a chronic feeling of hunger that, coupled with a metabolism that utilizes drastically fewer calories than normal, can lead to excessive eating and life-threatening obesity."

On its website, the International Prader-Willi Syndrome Organization (IPWSO) notes that the two "hallmark characteristics" of Prader-Willi Syndrome are extraordinarily low metabolism and an insatiable hunger.

The IPWSO website also features a quote from Dr. Hans Zellwegger (a pioneering researcher in the field of pediatrics and genetics) about the degree to which the compulsions associated with Prader-Willi Syndrome can overtake the lives of sufferers and their families:

PWS children constantly appear plagued by a relentless hunger that dominates their lives. The presence of this insatiable urge to eat, which is beyond the control of the patient, his family, or physician, becomes the primary focus for the child and inhibits all other activities and interest. ... Parents, usually unable to manage diets, food-seeking activities, and bizarre behavior, become distraught and emotionally drained.

Other Symptoms

In addition to an overwhelming hunger that can lead to childhood obesity, other symptoms of Prader-Willi Syndrome include:

• Low muscle tone and short stature
• Small hands and feet
• Poor motor skills
• Reduced bone mineral density (which may increase the risk of osteoporosis)
• Delayed or incomplete sexual development
• Learning problems (including mild to moderate mental retardation)
• Distinctive facial features (including a narrow face, small mouth, and full cheeks)

Prader-Willi Syndrome & Childhood Obesity

The "Rare Diseases" section of the informational website About.com provides the following information about the progression of Prader-Willi symptoms as they relate to overeating and childhood obesity:

At first, an infant with Prader-Willi syndrome will have trouble growing and gaining weight (failure to thrive). Because of weak muscles (hypotonia), the infant is not able to drink from a bottle, and may need special feeding techniques or tube feedings until his/her muscles become stronger. Infants with Prader-Willi syndrome are often behind other children in development.

Between ages 1-6 years the child with Prader-Willi syndrome suddenly develops a tremendous interest in food, and starts overeating. It is believed that the child with Prader-Willi never feels full after eating, and may actually go on eating binges.

Parents of children with the syndrome often have to lock the kitchen cabinets and refrigerator to restrict the child’s access to food. Children gain weight rapidly at this age.

The obesity-related aspects of Prader-Willi Syndrome are often brought under control as the child ages and becomes more receptive to eating a balanced low-calorie diet and getting regular amounts of exercise.

Treatment Options

Though there is no cure for Prader-Willi Syndrome, some of the symptoms can be addressed via medical intervention or behavioral modification. An IPWSO publication titled "A Comprehensive Team Approach to the Management of Prader-Willi Syndrome," reports that individuals with the disorder are best served by a multidisciplinary effort that provides the following:

• Growth hormone replacement
• Physical and occupational therapy
• Speech and language support
• Learning disability services
• Behavior management assistance
• Family interaction, support, and care

The Prader-Willi Syndrome Association reports that no appetite suppressant has been discovered that will consistently alleviate hunger pangs in people who have the syndrome. Most PWS patients, the association reports, need to remain on a low-calorie diet, and may require continued supervision to limit their access to food throughout their adult lives.