Since the time of Garrod, many of the intermediate steps of metabolism have been precisely characterized, defects pinpointed and genes identified. Certain liver diseases can be clearly attributed to mutations of genetic material resulting in alterations of metabolism or transport. Various types of metabolic disorders, each of which causes serious liver disease by quite different pathophysiologic mechanisms, are described in this paper. Metabolic disease can mimic any form of acute or chronic liver disease. Prompt recognition is crucial since some of these disorders are treatable, often dramatically so. Precise diagnosis is also imperative in order to inform the patient and their family of the genetic nature of the illness and the risk for recurrence.