The Irish National Alpha-1 Antitrypsin Deficiency (AATD) Registry: Examining the Prevalence of Radiological Abnormalities in a Population With Severe AATD.

Background Alpha-1 antitrypsin deficiency (AATD) is a genetic disorder that predisposes to early-onset emphysema. While severe AATD is a strong risk factor for early-onset emphysema, not every affected individual will develop it. This study describes the radiological findings in a cohort of patients with severe AATD upon first presentation at the National Specialist Alpha-1 Clinic, Dublin, Ireland, with special emphasis on the role of smoking and mode of ascertainment in AATD. Methods All data were obtained from the Irish National AATD Registry. This was a retrospective registry-based study and included entries from 2007 up until 2014. The study assessed 133 subjects who either had serum alpha-1 antitrypsin levels of ≤ 0.57 g/L (11 μmol/L) determined by immune turbidimetry or a ZZ variant identified by isoelectric focusing. Results On CT, 38 (28.6%) participants showed emphysema, 24 (18.0%) showed bronchiectasis, 41 (30.8%) showed both emphysema and bronchiectasis, nine (6.8%) showed other lung abnormalities, while 21 (15.8%) had normal findings. Ever-smokers had a higher percentage of emphysema findings compared to never-smokers (adjusted p = 0.0015), as did individuals diagnosed through symptomatic presentation rather than family screening (adjusted p = 0.045). Conclusions This study demonstrates that radiological abnormalities are common among individuals with severe AATD within the Irish National AATD Registry cohort, with emphysema and bronchiectasis representing key CT findings. The results also suggest that both smoking status and mode of ascertainment may influence the prevalence of these abnormalities.