Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) guanidinoacetate methyltransferase deficiency ?
    ### Response:
    Guanidinoacetate methyltransferase deficiency is an inherited disorder that primarily affects the brain and muscles. Without early treatment, people with this disorder have neurological problems that are usually severe. These problems include intellectual disability, speech development limited to a few words, and recurrent seizures (epilepsy).
    