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