This is common for Caucasians, but rare for African populations. As a CYP3A5 non-expressor you are unable to metabolize some common medications. This influences the synthesis of cholesterol, steroids and other lipids. The enzyme metabolizes drugs such as olanzapine, tacrolimus, nifedipine and cyclosporine as well as the steroid hormones testosterone, progesterone and androstenedione.
See the discussion at