ORLANDO, Fla.—Patients with Prader-Willi syndrome (PWS) commonly experience serious medical events, with those related to mental health and behavior occurring most frequently, according to a presentation made at the Prader-Willi Syndrome Association’s 2023 National Convention.

At least 1 serious medical event has been documented in 48% of participants in the Paving the Way for Advances in Treatment and Health (PATH) for PWS study, coordinator Lisa Matesevac said. Among those patients, 84% have had multiple serious medical events during the study.

The parent-reported PATH registry was launched in October 2018 to understand the incidence of serious medical events, such as hospitalization and emergency room visits, in patients with PWS. Its secondary objectives are to assess PWS behaviors over time, weight increases, use of prescription medication, and thrombotic events.

The study enrolled 700 caregiver participants, 647 of whom completed initial surveys. It has had 84% retention, 60% of whom have completed final surveys; the rest of the active participants will do so later this year.

Enhancing Development of the Hypothalamus Could Help Treat PWS

The study, which is part of the Global PWS Registry, has thus far documented a total of 600 serious medical events among participants, said Matesevac, who has a teenage son, Evan, with PWS.

“We have seen a higher incidence of serious medical events in older individuals, and we’ve also seen a higher incidence of multiple events occurring in older individuals,” she said.

Posters at the Prader-Willi Syndrome Association’s 2023 National Convention included one on the Paving the Way for Advances in Treatment and Health (PATH) for PWS study. (Photo by Terri Airov)

Aside from mental health and behavior-related events, the most common types of events have been seizures, gastrointestinal-related issues, orthopedic issues such as spinal surgeries and broken bones, and infections, according to the presentation.

The most frequently reported type of event in the mental health and behavior realm was extreme aggression, including incidents that resulted in a trip to the emergency room, police intervention, or someone being injured.

In the study, caregivers complete a set of surveys every 6 months. According to Matesevac’s presentation:

  • There is an equal distribution of male and female participants
  • The genetic subtypes are “pretty representative of the PWS population as a whole”
  • The majority of the participants live in the US, but the cohort also includes participants from 4 other countries
  • More than half of the patients with PWS are now adults
  • 31% of the study participants have also participated in a clinical trial during the study.

The study team published a study in 2022 on thrombosis risk history. They found that the risk of thrombosis appeared to increase with age, and 8% of patients aged more than 30 years had a documented blood clot.

As the final surveys are completed later this year, researchers plan to use validated measures, such as the PROMIS quality of life scale, to analyze the data. They will also examine subgroups of patients, particularly those aged more than 30 years, who make up about 20% of the participants overall.

Other goals include examining morbidly obese subgroups, understanding challenges among patients who have surgery for scoliosis, looking further at polypharmacy, and reviewing changes in patients’ behavior over time.


Matesevac L. PATH for PWS study 2023 update: a non-interventional, observational, natural history study of serious medical events in Prader-Willi syndrome (PWS). Oral presentation at: PWSA | USA 2023 National Convention; June 21, 2023; Orlando, FL.