Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes ?
    ### Response:
    Mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS) is a condition that affects many of the body's systems, particularly the brain and nervous system (encephalo-) and muscles (myopathy). The signs and symptoms of this disorder most often appear in childhood following a period of normal development, although they can begin at any age.
    