Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Sturge-Weber syndrome ?
    ### Response:
    Sturge-Weber syndrome is a rare disorder that is present at birth. Affected individuals have a large port-wine stain birthmark on their face, which is caused by blood vessel abnormalities. People with Sturge-Weber syndrome also develop blood vessel abnormalities in the brain called leptomeningeal angiomas.
    