Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) protein S deficiency ?
    ### Response:
    Protein S deficiency is a disorder of blood clotting. People with this condition have an increased risk of developing abnormal blood clots.  Individuals with mild protein S deficiency are at risk of a type of clot called a deep vein thrombosis (DVT) that occurs in the deep veins of the arms or legs.
    