Prader-Willi Syndrome

Chromosome 15 disorder

Prader-Willi syndrome. Credit: RJ Sangosti / Contributor / Getty Images

Prader-Willi syndrome is caused by a genetic disorder of chromosome 15. It is a rare disorder present at birth that results in a number of physical, mental and behavioral problems. A key feature of Prader-Willi syndrome is a constant sense of hunger that usually begins at about 2 years of age.

People with Prader-Willi syndrome want to eat constantly because they never feel full (hyperphagia) and usually have trouble controlling their weight.

Many complications of Prader-Willi syndrome are due to obesity.

If you or your child has Prader-Willi syndrome, a team of specialists can work with you to manage symptoms, reduce the risk of developing complications and improve quality of life.

Prader-Willi occurs in approximately one of every 12,000-15,000 people, in both boys and girls, and in people of all ethnic backgrounds. Prader-Willi syndrome is usually diagnosed by the appearance and behaviors of a child, then confirmed by specialized genetic testing of a blood sample. Although rare, Prader-Willi syndrome is the most common genetic cause of obesity.

Symptoms of Prader-Willi Syndrome

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.

Rate of Growth Slows

In addition to overeating, the child with Prader-Willi stops growing at a normal rate. The child gradually becomes short for his/her age, and because of overeating becomes excessively overweight.

Children with Prader-Willi syndrome have endocrine problems including reduced or absent secretion of sex hormones (hypogonadism) and delayed or incomplete sexual development. Children with the syndrome may also have mild to moderate mental retardation or learning problems, and may have behavior problems such as obsession, compulsion, stubbornness, and temper tantrums.

Distinctive facial features

Distinctive facial features also identify a child with Prader-Willi syndrome. These include a narrow face, almond-shaped eyes, small-appearing mouth, a thin upper lip with downturned corners of the mouth, and full cheeks.

The child's eyes may cross (strabismus).

Treatment of Prader-Willi Syndrome

There is no cure for Prader-Willi syndrome. However, the physical problems caused by the syndrome can be managed. During infancy, special feeding techniques and formulas can help the infant grow. Physical therapy and exercise helps improve strength and coordination. Administering human growth hormone (Genotropin, Humatrope, Norditropin) improves muscle mass and growth.

Speech therapy can help children who are behind in their language skills to catch up to their peers. Special education services and supports help children with Prader-Willi achieve their full capacity.

As the child grows, eating and weight problems can by controlled through a balanced, low-calorie diet, weight monitoring, external food restriction, and daily exercise.

References:

Mayo Clinic. Prader-Willi Syndrome. http://www.mayoclinic.org/diseases-conditions/prader-willi-syndrome/basics/definition/con-20028982

National Organization for Rare Disorders. Prader-Willi Syndrome.

Prader-Willi Syndrome Association (USA). Frequently Asked Questions About Prader-Willi Syndrome.

Scheimann, A. (2006). Prader-Willi Syndrome. eMedicine, accessed at http://www.emedicine.com/ped/topic1880.htm

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