Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) hereditary antithrombin deficiency ?
    ### Response:
    Hereditary antithrombin deficiency is a disorder of blood clotting. People with this condition are at higher than average risk for developing abnormal blood clots, particularly a type of clot that occurs in the deep veins of the legs. This type of clot is called a deep vein thrombosis (DVT).
    