A possible genetic influence in parenchyma and small airway changes in COPD: a pilot study of twins using HRCT.

Unlabelled: Genetic effects that contribute to the risk of developing chronic obstructive pulmonary disease (COPD) have been reported. Our purpose was to estimate the possible genetic influence on CT features related to COPD in twins.

Methods: Two COPD-discordant and one COPD-concordant monozygotic (MZ) twin pair, in addition to 2 control dizygotic (DZ) twin pairs underwent a low-dose high resolution computer tomography (HRCT) in inspiration and expiration (Philips Brilliance 16).

Results: Monozygotic twins were more similar in lung volume expiration and in air trapping score compared to dizygotics (382 cm(3) vs. 2303 cm(3) and 17.6% vs. 26.6%, respectively). In general, MZ twin pairs showed almost identical HRCT features independently of smoking attitude and COPD status. The dizygotic twin pairs showed larger differences in HRCT features compared to MZ twins.

Conclusions: Lung parenchymal and small airway changes (lung density, presence of bronchial wall thickening, bronchiectasis and/or mucus plug formation, air trapping and emphysema score) seem to be genetically associated traits, independently of smoking/COPD history. A future study with a larger sample size should confirm our findings.