Genetic Studies of Non-Alcoholic Fatty Liver Disease

* INCLUSION CRITERIA: 1. Although a liver biopsy is necessary to make the diagnosis of NASH, patients with radiologic evidence of fatty liver and/or cirrhosis in which other causes have been ruled out are eligible to participate. 2. Patients who have already undergone liver transplantation for a confirmed diagnosis of NAFLD or cryptogenic cirrhosis are also eligible to participate. 3. Depending on their willingness to participate, subjects may enroll in DNA laboratory-only or clinical-only. However, to conserve resources and meet study objectives, subjects with known pathogenic mutations will be given priority in selection for extensive clinical studies. 4. Direct blood relatives (typically parents and siblings) of affected individuals with NAFLD and associated conditions are also eligible to participate. EXCLUSION CRITERIA: 1. Anyone unwilling to provide informed consent (for themselves as adults, or on behalf of their children as minors) or assent. 2. Pregnant women. Although fatty liver and cirrhosis are sometimes diagnosed during pregnancy, it is unclear if they were present before and just not diagnosed or if they develop as a complication of pregnancy. Additionally energy metabolism changes during pregnancy and lactation which may confound our analysis. If the condition persists after pregnancy and the diagnosis of NAFLD is clearly established, patients can be referred to the study. 3. We will review a clinical description from the referring physician about a potential research subject to determine that the subject is appropriate to enter into the study. We reserve the right to exclude cases that are clearly not NAFLD or related to our direct research interests (e.g. fatty liver induced by chronic alcohol use, infectious causes, drug-related, or toxin-related). This almost never happens. However, as some of these environmental factors may contribute to a multifactorial etiology of hepatic changes, we may not exclude all such cases.