Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) pontocerebellar hypoplasia ?
    ### Response:
    Pontocerebellar hypoplasia is a group of related conditions that affect the development of the brain. The term "pontocerebellar" refers to the pons and the cerebellum, which are the brain structures that are most severely affected in many forms of this disorder.
    