National Institutes of Health (NIH) researchers and collaborators have found that being a carrier for sickle cell disease, known as having sickle cell trait, increases the risk of blood clots.
The study provides estimated clinical risks for people with sickle cell trait, which can inform clinical practice guidelines. Researchers examined data from over 19,000 people of various ancestral backgrounds with sickle cell trait.
The study, published in Blood Advances, was led by researchers at National Human Genome Research Institute (NHGRI), part of NIH, The Johns Hopkins University School of Medicine, Baltimore, and the company 23andMe, South San Francisco, California.
Individuals in this study are part of the 23andMe research program and have volunteered to participate in the research online and provided informed consent, which includes allowing their de-identified data to be analyzed and subsequently shared with research collaborators. Using data from this research cohort, which consists of over four million participants, researchers calculated the risk of blood clots in the veins, also known as venous thromboembolism. Through statistical analyses, participants were grouped based on their genetic similarities into genetic ancestry groups. The study found that people with sickle cell trait have a 1.45-fold higher risk of venous thromboembolism than those without sickle cell trait, a risk that is similar across all studied genetic ancestry groups.
To help clinicians estimate the risk of blood clots in people with sickle cell trait in comparison to other genetic carrier states, the researchers analyzed risk in people who are carriers for Factor V Leiden, a well-known inherited blood-clotting disorder. The study found that carriers for Factor V Leiden, which is more prevalent in people of European genetic ancestries, had an even higher risk of venous thromboembolism than people with sickle cell trait.
The researchers found that people with sickle cell trait have a higher risk of a type of blood clot called pulmonary embolism than those without sickle cell trait. Pulmonary embolism occurs when a blood clot breaks loose from deep veins, travels through the blood stream, reaches the lungs and stops blood flow. While people who experience pulmonary embolism may not always have symptoms, they might experience shortness of breath, chest pain and fainting.
