Below is an instruction from Human. Write a response.
    ### Instruction:
    What causes Non-classic congenital adrenal hyperplasia due to 21-hydroxylase deficiency ?
    ### Response:
    What causes non-classic congenital adrenal hyperplasia due to 21-hydroxylase deficiency? Non-classic congenital adrenal hyperplasia due to 21-hydroxylase deficiency (NCAH) is caused by changes (mutations) in the CYP21A2 gene. This gene provides instructions for making an enzyme called 21-hydroxylase, which is found in the adrenal glands.
    