SNP Shot: Genomic Insights

Protein S deficiency is a blood clotting problem where affected individuals have a higher chance of developing unusual blood clots.

People with a less severe form of protein S deficiency are prone to deep vein thrombosis (DVT), a clot that forms in the deep veins of the arms or legs. A DVT can become a pulmonary embolism (PE) if it travels to the lungs, which is a dangerous and potentially fatal situation. Several factors, such as older age, surgery, lack of movement, or pregnancy, can further increase the risk of blood clots in these individuals. Having protein S deficiency along with other inherited clotting disorders can also impact the likelihood of clot formation. It's important to note that many individuals with mild protein S deficiency may never experience an abnormal blood clot.

In severe protein S deficiency, newborns can develop a life-threatening condition called purpura fulminans shortly after birth. This condition involves widespread blood clot formation in small blood vessels throughout the body. These clots disrupt normal blood flow, potentially leading to tissue death (necrosis). The extensive clotting process depletes the body's clotting proteins, resulting in abnormal bleeding in various areas, often manifesting as large, purple skin lesions. Infants who survive the initial period may experience recurring episodes of purpura fulminans.

Inheritance:

Protein S deficiency follows an autosomal dominant inheritance pattern. This means that inheriting just one altered copy of the PROS1 gene in each cell is enough to cause a mild form of the deficiency. Individuals who inherit two altered copies of the gene, one from each parent, develop the severe form of protein S deficiency.