Prader-Willi Syndrome: An Overview

Achievement Center of Texas' Prader-Willi Syndrome Center can and will cater to those with Prader-Willi syndrome. It is a complex genetic condition that affects many parts of the body. In infancy, PWS will cause weak muscle tone, feeding difficulties, poor growth, and delayed development.

Beginning in childhood, affected individuals develop an insatiable appetite, which leads to chronic overeating and obesity. Some people with Prader-Willi syndrome, particularly those with obesity, also develop type 2 diabetes. Although rare, Prader-Willi syndrome is the most common genetic cause of obesity.

People with Prader-Willi syndrome typically have mild to moderate intellectual impairment and learning disabilities. Behavioral problems are common, including temper outbursts, stubbornness, and compulsive behavior. Sleep abnormalities can also occur. These symptoms are of course treatable.

Additional features of this condition include distinctive facial features such as a narrow forehead, almond-shaped eyes, and a triangular mouth; short stature; and small hands and feet. Some people with Prader-Willi syndrome have unusually fair skin and light-colored hair. Both males and females affected have underdeveloped genitals.

Prader-Willi Syndrome Center
via Wikimedia Commons

Causes of Prader-Willi Syndrome (PWS)

Prader-Willi syndrome is caused by the loss of function of genes in a specific part of chromosome 15. People normally inherit one copy of this chromosome from each parent.

Most cases of Prader-Willi syndrome, about 70 percent, occur when a segment of the paternal chromosome 15 is deleted. In another 25 percent of cases, a person with Prader-Willi syndrome has two copies of chromosome 15 inherited from their mother instead of one copy from each parent. This phenomenon is called maternal uniparental disomy.

Missing Genes

It is likely that the characteristic features of Prader-Willi syndrome result from the loss of function in several genes on chromosome 15. Studies suggest that the loss of a group of snoRNA genes, known as the SNORD116 cluster, may play a major role in causing the signs and symptoms of Prader-Willi syndrome.

However, it is unknown how a missing SNORD116 cluster could contribute to intellectual disability, behavioral problems, and the physical features of the disorder.

In some people with Prader-Willi syndrome, the loss of a gene called OCA2  (located on the segment of chromosome 15) is associated with unusually fair skin and light-colored hair. The protein produced from this gene helps determine the coloring of the skin, hair, and eyes. However, loss of the OCA2 gene does not cause the other signs and symptoms of Prader-Willi syndrome.

Researchers are studying other genes on chromosome 15 that may also be related to the major signs and symptoms of this condition.

How ACT Helps Those with PWS

Parents can enroll infants with PWS in early intervention programs or special needs programs like the one our Prader-Willi Syndrome Center offers. The types of treatment depend on the individual’s symptoms. The health care provider may recommend the following:

  • Early interventions/Special needs programs
  • Physical therapy
  • Strict supervision of daily food intake
  • Use of special nipples or tubes for feeding difficulties
  • Growth Hormone (GH) therapy
  • Sleep studies and treatment
  • Medications
  • envolvement in group homes during adulthood

More information about services offered is here.