Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) medium-chain acyl-CoA dehydrogenase deficiency ?
    ### Response:
    Medium-chain acyl-CoA dehydrogenase (MCAD) deficiency is a condition that prevents the body from converting certain fats to energy, particularly during periods without food (fasting).  Signs and symptoms of MCAD deficiency typically appear during infancy or early childhood and can include vomiting, lack of energy (lethargy), and low blood sugar (hypoglycemia).
    