Although Prader-Willi syndrome (PWS) is associated with an abnormality of chromosome 15, it is generally considered not to be an inherited condition but rather a spontaneous genetic birth defect that occurs at or near the time of conception. The faulty chromosome affects functioning of the hypothalamus.
Newborns with the condition have poor muscle tone and cannot suck well enough to get sufficient nutrients. Often they must be fed through a tube for several months after birth until muscle control improves. Sometime in the following years, usually by preschool age, children with PWS develop an increased interest in food and quickly gain excessive weight if calories are not restricted.
In addition to sometimes extreme attempts to obtain food, children with PWS are prone to temper outbursts, stubbornness, rigidity, argumentativeness, and repetitive thoughts and behaviors. Strategies to deal with these problems usually include structuring the person’s environment, implementing behavioral management techniques, and occasionally using drug therapy.
Children with PWS can attend school, enjoy community activities, get jobs, and even move away from home, although they need a lot of help. School children with PWS are likely to need special education and related services, such as speech and occupational therapy. In community, work, and residential settings, adolescents often need special assistance to learn and carry out responsibilities and to get along with others.
Children with PWS need around-the-clock food supervision. When they grow up, most affected individuals do best in a special group home for people with PWS, where food access can be restricted without interfering with those who do not need such restriction. Although in the past many patients died in adolescence or young adulthood, preventing obesity will allow a person with PWS to live a normal lifespan.
Early diagnosis of Prader-Willi syndrome gives parents an opportunity to manage their child’s diet and avoid obesity and its related problems from the start. Since infants and young children with PWS typically have developmental delays in all areas, diagnosis may facilitate a family’s access to critical early intervention services and help identify areas of need or risk. Diagnosis also makes it possible for families to get information and support from professionals and other families who are dealing with the syndrome.
Many doctors will refer a suspected patient to a medical geneticist who specializes in diagnosing and testing for genetic conditions such as PWS. After taking a history and doing a physical examination, the diagnostician will arrange for specialized genetic testing to be done on a blood sample to evaluate for the genetic abnormality found in people with PWS.