PURPOSE: Alpha One Antitrypsin Deficiency (AATD) is a hereditary disorder characterized by deficiency in a serum protease inhibitor. This deficiency predisposes patients to early onset emphysema through uncontrolled proteolytic attack in the lung. There is great variability in the age of onset of clinically recognizable lung disease amongst AATD patients. Estimates of the frequency of deficiency phenotypes in the United States population predict anywhere from 40,000 to 100,000 patients should have AATD. Less than 7000 are currently diagnosed. We hypothesized that one reason for the expected/diagnosed discrepancy is the lack of testing in populations outside the ATS/ERS guidelines. Our clinic undertook a serial screening protocol of all obstructed lung disease patients, regardless of age, race or level of obstruction.
METHODS: Patients were approached for consent into the study if they demonstrated obstruction on pulmonary function testing (defined as an FEV1 of less than 80% predicted with normal volumes) or a diagnosis of an obstructive lung disease (asthma, COPD, Bronchiectasis), regardless of degree of obstruction.
RESULTS: 254 continuous consented obstructive lung disease patients were tested for AATD. Age ranged from 22 to 75. Four non-related AATD patients with PiZZ have been found to date, and 1 PiSZ has been found. 4 of the 5 patients were diagnosed over the age of 45, including one at age 62; well beyond the recommended age range of the ATS/ERS guidelines. Each patient had greater than a 20-pack year tobacco history.
CONCLUSION: AATD is a serious under-diagnosed medical condition that leads to significant morbidity and mortality. The ATS/ERS guidelines suggest testing in pre-defined settings of disease, such as early-onset emphysema and family history of early emphysema. However, our clinical experience in testing has revealed limitations in the current ATS/ERS guidelines.
CLINICAL IMPLICATIONS: Age of the patient and number of pack-years should not dictate testing for AATD. All obstructed patients should be offered AATD testing.
DISCLOSURE: Douglas Hogarth, No Product/Research Disclosure Information; Other free AATD test kits provided by Baxter