Primary biliary cirrhosis (PBC) is a chronic liver disease primarily affecting middle age women. It is characterized by immune-mediated damage to cells lining the tiny bile ducts within the liver. Although the underlying cause of PBC is likely to be multifactorial, the epidemiologic/population data indicate a very important role for genetic predisposition, meaning that the disease seems to run in families. Susceptibility genes for PBC have not been identified possibly due to limitations such as small sample size in prior studies. The primary objective of this study is to identify these genes. This study involves obtaining clinical and demographic data as well as collecting DNA samples from patients and their parents, and siblings to screen for a select set of candidate genes as well as the full genome for variants associated with PBC.