Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Aberrant subclavian artery ?
    ### Response:
    Aberrant subclavian artery is a rare vascular anomaly that is present from birth. It usually causes no symptoms and is often discovered as an incidental finding (such as through a barium swallow or echocardiogram). Occasionally the anomaly causes swallowing difficulty (dysphagia lusoria).
    