My 49 yr old son first became aware of high alt#'s in 2008. Tests have ruled out hepatitis c, cirrhosis, and a tumor. What else could cause this?

Some ideas. We want to rule out hemochromatosis first and foremost. Wilson's may still be a consideration even at his age. Autoimmune hepatitis is less likely, and antitrypsin deficiency less treatable, both could be tested for. I trust he did not drink or take any meds including Ibuprofen during the workup. Most likely is metabolic syndrome with a rx for aerobic fitness.