Although rare overall, people with PWS have a higher risk for developing dangerous blood clots than the general population. A blood clot is a mass of blood that has changed from its liquid state into a semi-solid or gel-like form.
Clotting is a natural process that helps stop bleeding when a blood vessel is injured, however, blood clots can sometimes form inappropriately inside blood vessels, potentially blocking blood flow. When this happens, the clot can cause health issues like deep vein thrombosis (DVT), which is a clot in a deep vein (often in the leg), or pulmonary embolism (PE), where a clot travels to the lungs.
In a review of 883 individuals with PWS who completed the Thrombosis Risk Survey in the Global PWS Registry, 3.6% of the participants with PWS had a history of blood clots (Matesevac et al, 2022). This is significantly higher than what is reported for the general population (<1%).
The prevalence of blood clots increased with age, such that 8% of individuals 30 years or older reported at least one blood clot. Of those individuals with a history of blood clots, 50% reported this first occurred between 18-29 years of age and 31.25% reported the first event occurred at age 17 or younger. This represents a much higher frequency of blood clots in PWS compared to the general population, where the risk for blood clots is approximately 1% at age 80 years or older. Additionally, the age of onset is much younger in PWS compared to the general population.
Of significance, those with a history of edema (excess fluid in body tissues) were found to have a higher prevalence of blood clots compared to those with no history or unknown history of edema. Also of note, when comparing those with a known PWS subtype, a statistically significant difference was found among those with Deletion having blood clots (4.9%) as compared to UPD (1.4%). However, another study in PWS (Manzardo et al 2019) did not see a difference by genetic subtype, but did find increased risk of blood clots for those individuals with obesity, edema, high blood pressure or vasculitis (inflammation in the blood vessels).
What Increases the Risk of Blood Clots?
There are some factors that may increase your chances of developing dangerous blood clots. They include:
- Genetic blood clotting disorder / family history of blood clots
- Smoking
- Being overweight or obese
- Sitting or lying still for a prolonged period of time
- Hormonal birth control or hormone replacement therapy
- Recent surgery or severe bruising (injury to the veins)
- High blood pressure
- Older age
Signs and Symptoms of Blood Clots
Deep vein thrombosis (DVT) happens when blood clots form in the deep veins of the legs. The most common symptoms of DVT include:
- Swelling in the affected leg
- Pain in the affected leg (may feel like cramping in the calf)
- Affected area feeling warm and tender
- Redness or other changes in skin color, such as the skin turning paler or having a bluish tint
If you see evidence of a DVT in your loved one with PWS, you should contact your doctor immediately or go to the emergency room.
Pulmonary embolism (PE) develops when a blood clot in the deep veins of the leg (DVT) breaks loose, travels through the bloodstream, and becomes lodged in the lungs. Symptoms of PE include:
- Shortness of breath
- Problems breathing
- Coughing up blood
- Light-headedness, fainting, and unconsciousness
- Sharp chest pain that worsens after taking a deep breath
PLEASE NOTE: Symptoms of PE can occur very suddenly and without warning. These symptoms need medical attention at once. CALL 911 OR GO TO THE EMERGENCY ROOM IMMEDIATELY.
Learn more about the signs and symptoms of blood clots with our Fact Sheet.
