Prader-Willi syndrome is a rare disorder present at birth that results in a number of physical, mental and behavioral problems. A key feature of Prader-Willi (prah-dur VIL-ee) syndrome is a constant sense of hunger that usually begins after the first year of life.
People with Prader-Willi syndrome want to eat constantly and usually have trouble controlling their weight. Many complications of Prader-Willi syndrome are due to obesity.
If your child has Prader-Willi syndrome, a team of specialists can work with you to manage your child's symptoms and reduce the risk of developing complications.
Other signs and symptoms of Prader-Willi syndrome may include:
When to see a doctor
See your doctor if your infant:
See your doctor if your older child shows any of the following signs:
Prader-Willi syndrome is a genetic disorder, a condition caused by an error in a gene or genes. Although the exact genes responsible for Prader-Willi syndrome haven't been identified, the problem is known to lie in a particular region of chromosome 15.
With the exceptions of genes related to sex characteristics, all genes come in pairs, one copy inherited from your father (paternal gene) and one copy inherited from your mother (maternal gene). For most types of genes, if one copy is "active," or expressed, then the other copy also is expressed.
However, some types of genes act alone. In other words, it's normal with certain genes for the paternal gene to be expressed and the maternal gene to be "silent."
What happens in Prader-Willi syndrome
The genetic defect of Prader-Willi syndrome disrupts the normal functions of a portion of the brain called the hypothalamus. Among its many functions, the hypothalamus controls hunger and thirst and releases hormones that prompt the release of other substances responsible for growth and sexual development. A malfunctioning hypothalamus — caused by the defect on chromosome 15 — interferes with each of these processes, resulting in uncontrollable hunger, stunted growth, sexual underdevelopment and other characteristics of Prader-Willi syndrome.
Complications of hypogonadism
Preparing for your appointment
At each visit your child's doctor will measure your baby's height, weight and head circumference. This enables your doctor to track changes and identify problems. The doctor will also test your child's muscle tone by seeing how your child responds to having his or her legs and arms moved. The complete physical exam will include checking the genitals for abnormalities.
Be prepared to answer questions that your baby's doctor is likely to ask:
If you have any concerns about your baby's health between well-baby visits, schedule an appointment.
If your doctor believes that your child exhibits signs of Prader-Willi syndrome or suggests diagnostic tests for the disorder, consider asking the following questions:
Tests and diagnosis
In infants, signs that may prompt your doctor to request a blood test for Prader-Willi syndrome include:
In older children, your child's doctor may suspect Prader-Willi syndrome if your child exhibits:
A definitive diagnosis can almost always be made with a laboratory test. Special genetic tests can identify abnormalities in your child's chromosomes that are characteristic of Prader-Willi syndrome.
Treatments and drugs
A team of health professionals will likely work with you to manage your child's condition. Most children with Prader-Willi syndrome will need the following care and treatments:
Other treatments may be necessary depending on the specific symptoms your child has or complications that develop.
Transition to adult care
Organizations, such as the Prader-Willi Syndrome Association, can help families find local resources and services.
Also, talk to your child's doctor for suggestions about making the transition to adult medical care.
Lifestyle and home remedies
Tips to help you take care of your child with Prader-Willi syndrome include the following:
Coping and support
Having a child with Prader-Willi syndrome and its associated behavioral problems is challenging and can take a lot of patience. Some people find it helpful to talk with others who share similar experiences. Ask your doctor about family support groups in your area. Organizations such as the Prader-Willi Syndrome Association provide resources, support groups and educational materials. You can reach the Prader-Willi Association at 800-926-4797.
Defective or missing portions of paternal genes responsible for Prader-Willi syndrome usually occur randomly. This means that in most instances, Prader-Willi syndrome can't be prevented. However, in a small number of cases, a genetic mutation inherited from the father may cause Prader-Willi syndrome.
If you have a child with Prader-Willi syndrome and would like to have another baby, consider seeking genetic counseling. A genetic counselor may help determine your risk of having another child with Prader-Willi syndrome.
Last Updated: 2011-04-12
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