Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Familial hemiplegic migraine type 1 ?
    ### Response:
    Familial hemiplegic migraine (FHM) is a form of migraine headache that runs in families. Migraines usually cause intense, throbbing pain in one area of the head, often accompanied by nausea, vomiting, and extreme sensitivity to light and sound. These recurrent headaches typically begin in childhood or adolescence and may last from a few hours to a few days.
    