The cause of liver disease depends on the type of disease. In many cases, particularly with diseases that are present at birth, the cause is unknown. Causes and risk factors for specific types of liver disease may include:

• Budd Chiari syndrome. In most cases, the cause of Budd Chiari syndrome is unknown. Some patients with this condition also have polycythemia vera (an abnormal increase in blood cells that results from excess production by the bone marrow). Pregnancy, chronic infections, certain diseases, tumors and the use of birth control pills may cause the condition in some people. Most people with this condition are between ages 20 and 40.
  
  
• Cirrhosis. In the United States, the most common causes of cirrhosis are alcoholism and hepatitis B and C. People who drink excessive amounts of alcohol, engage in unsafe sexual practices and share needles for intravenous drug use have a higher risk for developing cirrhosis.
  
  
• Fatty liver. All the causes of fatty liver have not yet been identified. In the United States and other Western countries, the most common causes of fatty liver include alcohol abuse, obesity and diabetes (a disorder in the body’s ability to use blood sugar [glucose]). Nonalcoholic fatty liver disease, also called nonalcoholic steatohepatitis (NASH) is strongly associated with obesity, high blood pressure, high cholesterol levels and diabetes.
  
  
• Gilbert syndrome. Patients with this condition have an inherited genetic abnormality that causes reduced levels of an enzyme in bilirubin to be produced. As a result, a type of bilirubin (called unconjugated bilirubin) accumulates in the blood. However, patients do not have acute or chronic liver disease.
  
  
• Glycogen storage disease. Most patients with this disease inherited certain types of genes from their parents that lead to development of the condition.
  
  
• Hemochromatosis. In the United States, a large percentage of patients with this condition inherit a certain type of gene from their parents. However, not everybody who inherits these genes develops the condition.
  
  
• Hepatitis. Viral hepatitis is caused by exposure to the hepatitis A, B, C, D or E viruses. The viruses live in blood, body fluids and feces. They can be spread through food or water that is contaminated by feces, through sexual contact with an infected person, from mother to child during childbirth and through shared needles during intravenous drug use.
  
  
• Liver cancer. It is not clear what causes liver cancer, but risk factors for developing the disease may include exposure to the hepatitis B and C viruses, cirrhosis and excessive alcohol consumption.
  
  
• Liver failure. Acetaminophen is one of the most popular over-the-counter painkillers. Researchers have found a growing incidence of acute liver failure in recent years. Much of this increase is attributed to unintentional and sometimes intentional overdose of acetaminophen. Liver failure can also result from late stages of diseases such as cirrhosis or hepatitis.
  
  
• Wilson's disease. Most patients with this disease inherited certain type of genes from their parents that results in development of the disease.