Genetic diseases are those that are passed down from parent to child through defective genes. Genes are the units of deoxyribose nucleic acid (DNA) that carry the code for a specific trait. Defects in genes that code for specific proteins and functions controlled by the liver can result in liver disease. Some genetic liver diseases are common while others are rare.
Alpha-1 Antitrypsin Deficiency
Alpha-1 antitrypsin is a protein that is produced in the liver. When the gene that codes for this protein is defective, the liver is not able to produce it, resulting in a deficiency of this protein. A person who inherits one defective gene can still produce enough of the protein and is called a carrier. Those who have two defective copies will have the disease.
The function of the alpha-1 antitrypsin protein is to protect the lungs from an enzyme, called neutrophil elastase. Neutrophil elastase helps the lungs heal by digesting bacteria and dead or damaged cells; however, when the levels are not controlled by alpha-1 antitrypsin, lung damage can occur. In addition to lung damage, alpha-1 antitrypsin can cause cirrhosis of the liver, which will affect 12 to 15 percent of alpha-1 patients, according to the Alpha-1 Association. Cirrhosis of the liver is the build-up of scar tissue in the liver and can inhibit liver function.
Wilson's Disease
Wilson's disease is caused by a genetic defect in the ATP7B gene. This defective gene inhibits the liver's ability to filter copper from the body, releasing it in the bile. As copper builds up in the liver, it leaks into the bloodstream where it can travel to other organs, including the brain, kidneys and eyes, and cause damage. If left untreated, Wilson's disease can cause brain damage and liver failure.
Familial Amyloidosis
Familial amyloidosis is a disease that occurs as a result of a defective gene that codes for plasma proteins produced in the liver. The defect causes the proteins to accumulate, forming amyloid deposits. These deposits interfere with normal organ functions and can cause nerve damage, cardiovascular problems and kidney problems.
Hereditary Hemochromatosis
Hereditary hemochromatosis is a recessive genetic disorder, meaning that the person affected must have two copies of the defective gene in order for the disease to occur. It is caused by a defect in the gene known as HFE, which is responsible for producing protein that regulates the amount of iron absorbed from food.
Those who have hereditary hemochromatosis absorb too much iron, which is often stored in the liver. The excess iron can cause liver disease, including cirrhosis of the liver, and even lead to liver cancer. This disease is the most common iron overload disease, occurring in approximately 0.05 percent of the Caucasians in the United States, according to the Human Genome Project.
