Alpha-1 antitrypsin deficiency

Alternative names:

AAT deficiency

Definition:

A deficiency of a protein produced in the liver that blocks the destructive effects of certain enzymes and is associated with emphysema and liver disease.

Causes, incidence, and risk factors:

Alpha-1 antitrypsin deficiency results from a genetic defect. The mechanism that causes associated liver disease and emphysema in some people with this deficiency is unknown, although it may be related to inflammation. Up to 25% of children with AAT deficiency develop liver cirrhosis. Approximately 75% of adults with this deficiency develop emphysema. The emphysema often begins before 40 years of age and occurs more frequently than expected in women. The incidence of AAT deficiency is 1 out of 10,000 people.