Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Wyburn Mason's syndrome ?
    ### Response:
    Wyburn Mason's syndrome is a condition in which blood vessels do not form correctly in both the retina of one eye and a part of the brain.  These malformed blood vessels are called arteriovenous malformations (AVM).  Wyburn Mason's syndrome is present from birth (congenital) and the cause is unknown.
    