The purpose of this research study is to determine the way (mechanisms) by which your defect
in bile acid handling (metabolism) causes your liver disease or abnormality in absorption of
vitamins and the effect of an investigational bile acid therapy (glycocholic acid) on your
vitamin absorption and your liver disease. An investigational therapy is one that not
approved by the United States Food and Drug Administration (FDA) and is being provided to you
under an Investigational New Drug application from the FDA.