Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Microcephaly ?
    ### Response:
    Microcephaly is a medical condition in which the circumference of the head is smaller than normal because the brain has not developed properly or has stopped growing. Microcephaly can be present at birth or it may develop in the first few years of life. It is most often caused by genetic abnormalities that interfere with the growth of the cerebral cortex during the early months of fetal development.
    