Alpha-1 Antitrypsin Deficiency (AATD) is an uncommon – but not rare – genetic disease that seriously affects the lungs, occurring in about one of every 3,000 people.
Alpha-1 Antitrypsin (AAT) is an enzyme that protects our lungs from protein damage and neutrophil elastase. Neutrophils are one of the white blood cells in our blood stream that migrate into our lungs to help kill microbial viruses and bacteria. In the normal state of affairs the neutrophils release elastase and other chemicals that kill the microbes – which then need to be “mopped up,” so as not to hurt lung tissue.
This is the job of AAT; but if a person is deficient in AAT, the clean-up doesn’t occur, which leads to gradual chronic damage to the lungs. Neutrophils also respond to counter cigarette smoke and pollution.
The most common indicator of disease is onset of emphysema in younger adults. It can also play a role in COPD (Chronic Obstructive Pulmonary Disease), and some forms of asthma. In asthma that is difficult to control or poorly responsive to the usual therapies, AATD should be considered. It can also be a cause of bronchiecstasis (a difficult condition in which the airways slowly lose their ability to clear out mucus, leading to chronic damage and serious lung infections.)
The severity of the AAT deficiency and, thus the disease, can vary depending on inherited alternative forms of a gene. The level of AAT ranges from totally absent, to severely reduced to moderately reduced.
Patients whose level of AATD is below 11 micromoles can benefit from intravenous replacement therapy of the Alpha-1 enzyme.