Role of X chromosome defects in primary biliary cirrhosis.

Similar to the majority of autoimmune conditions, primary biliary cirrhosis (PBC) is a chronic cholestatic liver disease characterized by a striking female predominance; it is characterized by high titer serum autoantibodies to mitochondrial antigens, elevated serum immunoglobulin M, progressive destruction of intrahepatic bile ducts, and ultimately liver cirrhosis and failure. Familiarity and high concordance rates for the disease among monozygotic twins strongly support the role of genetics in the disease. Experimental efforts have been dedicated by our and other research groups to investigate the role of X chromosome abnormalities (i.e. monosomyrates and inactivation patterns) in autoimmunity. Our recent work has demonstrated enhanced X monosomy in women with PBC as well as two other female-predominant autoimmune diseases, systemic sclerosis and autoimmune thyroid disease. We will review herein the most recent evidence on the role of the X chromosome in PBC onset and discuss the potential implications. Future developments of these findings will be discussed.