Children's Hospital Colorado

Alpha-1 Antitrypsin Deficiency

What is alpha-1 antitrypsin deficiency?

Alpha-1 antitrypsin (AAT) deficiency is the most common genetic disorder leading to liver disease in infants and children. About 10 to 15% of children with alpha-1 antitrypsin deficiency will develop liver disease. In adults, it may also cause a serious lung disease called emphysema.

The deficiency is genetic, meaning that children inherit it from their parents.

What causes alpha-1 antitrypsin deficiency?

Genes make up our deoxyribonucleic acid (DNA), which acts as a blueprint for the body, telling it how to form and function. Alpha-1 antitrypsin deficiency is caused by mutations in the SERPINA1 gene that contains the instructions to make the alpha-1 antitrypsin protein.

Alpha-1 antitrypsin proteins are made in large amounts by the liver and put into the bloodstream to be distributed to the rest of the body. Because of these mutations in the SERPINA1 gene, the alpha-1 antitrypsin protein gets stuck in the liver, which causes inflammation (swelling) that can damage the liver.

Who gets alpha-1 antitrypsin deficiency?

Children inherit AAT deficiency from their parents. In general, people with the deficiency inherit one mutated copy of the SERPINA1 gene from each of their parents. It occurs in about one in every 3,500 births in the United States and is more common in Caucasians.