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The most common manifestation is venous thrombosis of the lower extremities (i.e. the legs), and this accounts for approximately 90% of all events associated with protein S deficiency. The other 10% of manifestations include those listed above. The warning signs for a venous thrombosis are generally pain, tenderness, redness, or swelling in extremity or affected areas. Approximately 60-80% of individuals with the inherited form of protein S deficiency will go on to have a venous thrombosis at some point in their life, with the majority occurring before ages 40-45. The remaining 20-40% are considered asymptomatic, meaning that they never go on to develop these clots. For individuals whose lives are shortened by protein S deficiency, the cause of death is a pulmonary embolism, or the passage of a blood clot to the lungs. Symptoms of a pulmonary embolus include difficulty breathing, abnormal coughing, chest pain, fainting or heart palpitations.