Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) carnitine palmitoyltransferase I deficiency ?
    ### Response:
    Carnitine palmitoyltransferase I (CPT I) deficiency is a condition that prevents the body from using certain fats for energy, particularly during periods without food (fasting). The severity of this condition varies among affected individuals.  Signs and symptoms of CPT I deficiency often appear during early childhood.
    