What is PWS?

Prader-Willi syndrome (PWS) is a genetic disorder that occurs in approximately one out of every 15,000 births. PWS affects males and females with equal frequency and affects all races and ethnicities. PWS is recognized as the most common genetic cause of life-threatening childhood obesity.

The common characteristics defined in the initial report included small hands and feet, abnormal growth and body composition (small stature, very low lean body mass, and early-onset childhood obesity), hypotonia (weak muscles) at birth, insatiable hunger, extreme obesity, and intellectual disability.

PWS results from an abnormality of chromosome 15, and definitive diagnosis is now based on genetic testing.

What are the symptoms of Prader-Willi syndrome?

The symptoms of Prader-Willi syndrome are likely due to dysfunction of a portion of the brain called the hypothalamus. The hypothalamus is a small endocrine organ at the base of the brain that plays a crucial role in many bodily functions, including regulating hunger and satiety, body temperature, pain, sleep-wake balance, fluid balance, emotions, and fertility. Although hypothalamic dysfunction is believed to lead to the symptoms of PWS, it is not yet clear how the genetic abnormality causes hypothalamic dysfunction.

There are two general stages of the symptoms associated with PWS:

Stage 1

In the first stage, infants with PWS are hypotonic or “floppy”, with very low muscle tone. A weak cry and a poor suck reflex are typical. Babies with PWS usually are unable to breastfeed and frequently require tube feeding. These infants may suffer from “failure to thrive” if feeding difficulties are not carefully monitored and treated. As these children grow older, strength and muscle tone generally improve. Motor milestones are achieved, but are usually delayed.

Stage 2

An unregulated appetite and easy weight gain characterize the second stage of PWS. This stage most commonly begins between ages 2 and 8 years old. Individuals with PWS lack normal hunger and satiety cues. They usually are not able to control their food intake and will overeat if not closely monitored. Food seeking behaviors are very common. In addition, the metabolic rate of persons with PWS is lower than normal. Left untreated, this combination of problems leads to morbid obesity and its many complications.

In addition to obesity, a variety of other symptoms can be associated with Prader-Willi syndrome. Individuals usually exhibit cognitive challenges, with measured IQs ranging from low normal to moderate intellectual disability. Those with normal IQs usually exhibit learning disabilities. Other issues may include growth hormone deficiency/short stature, small hands and feet, scoliosis, sleep disturbances with excessive daytime sleepiness, high pain threshold, speech apraxia/dyspraxia, and infertility. Behavioral difficulties may include obsessive-compulsive symptoms, skin picking, and difficulty controlling emotions. Adults with PWS are at increased risk for mental illness. PWS is a spectrum disorder and symptoms vary in severity and occurrence among individuals.

Is there a cure for Prader-Willi syndrome?

Currently, there is no cure for Prader-Willi syndrome, and most research to date has been targeted towards treating specific symptoms (see Diagnosis & Treatments). For many individuals affected by the disorder, the elimination of some of the most difficult aspects of the syndrome, such as the insatiable appetite and obesity, would represent a significant improvement in quality of life and the ability to live independently. The Foundation for Prader-Willi Research is interested in advancing research toward understanding and treating specific aspects of the syndrome, with the goal of an eventual cure for PWS.

How do these genetic defects cause the symptoms seen in Prader-Willi syndrome?

The PWS region of chromosome 15 is one of the most complex regions of the human genome. Although there have been significant advances in understanding and characterizing the genetic changes associated with PWS, the exact mechanism by which lack of functional genetic material in this region leads to the symptoms associated with PWS is not understood. Scientists are actively studying the normal role of the genetic sequences in the PWS region and how their loss affects the hypothalamus and other systems in the body.

Where do the Funds Go?

Funds from One SMALL Step walks are utilized by the Foundation for Prader-Willi Research (FPWR) to support investigator initiated grants, PWS clinical trials, resource sharing grants, and the Global PWS Registry.

FPWR is a nonprofit organization dedicated to fostering and supporting research that will advance the understanding and treatment of PWS. Our mission is to eliminate the challenges of PWS, through the advancement of research.

FPWR has funded PWS research projects from leading scientists and research laboratories around the world with topics covering:

Where can I learn more about PWS research and genetics?

Click here for more information on PWS, research, and where the funds go.

One SMALL Step Sponsors

Interested in becoming a corporate sponsor?

One SMALL Step, hosted by the Foundation for Prader-Willi Research, is an international event supported by Prader-Willi organizations and families around the world. Since it’s inception, One SMALL Step has raised funds to achieve the mission of FPWR: "to eliminate the challenges of PWS through the advancement of research." More than 7,000 walkers participate in One SMALL Step events every year and we are continuing to grow!

What are the benefits of teaming with One SMALL Step?

Taking One SMALL Step provides visibility for your company! Our PWS families are brand loyal and avid advocates. Sponsoring One SMALL Step puts your company logo in front of thousands of potential customers through:

The One Small Step Sponsorship Package is available upon request. Sponsorship packages may also be developed and specifically designed to meet the needs of the sponsor. We look forward to working with you to create a package that will help you achieve your corporate goals. To get started, please contact Director of One SMALL Step, Sarah Peden at Sarah.Peden@fpwr.org