AAT deficiency is a genetic disorder associated with emphysema. Spirometry, the lung function test that measures how well the lungs exhale air, is used to diagnose and track the progression of emphysema. Some studies have suggested that forced expiratory volume in 1 second (FEV1) measurements, a type of spirometry test, may lack accuracy in detecting disease progression in cases of severe AAT deficiency. Another method, high resolution chest CT scans, may be more accurate at measuring the progression of emphysema. The purpose of this study is to determine if high resolution CT scans are better at detecting the progression of emphysema than lung function tests. Results from this study may lead to the development of a more accurate way to assess lung tissue loss and may improve the understanding of lung destruction in AAT deficiency.~This study will last 4 years and will enroll people with AAT deficiency who have nearly normal lung function test results. Study visits, each lasting about 4 hours, will occur at baseline and months 6, 12, 18, 24, and 36. At each visit, participants will undergo lung function tests, a CT scan, blood collection, and a physical exam. Female participants will have urine collected for a pregnancy test. All participants will also complete questionnaires to assess health status and lung function. Study researchers will call participants every 2 months to collect information on lung disease symptoms and medication changes.
Individuals with a deficiency of alpha-1 antitrypsin (AAT) often develop emphysema. Traditional lung function tests may not be the most accurate way to measure the progression of emphysema. This study will compare high resolution computed tomography (CT) scans to spirometry to measure the progression of emphysema.