Quantitative analysis of lungs and airways with CT in subjects with the chronic obstructive pulmonary disease (COPD) candidate FAM13A gene: case control study for CT quantification in COPD risk gene.

OBJECTIVE:To investigate the relationship between a chronic obstructive pulmonary disease (COPD) candidate gene, based on a genomewide association study, and computed tomographic (CT) quantitative analysis; and to find a phenotype in the COPD candidate FAM13A gene. MATERIALS AND METHODS:This study was conducted in subclinical male smokers between 2 groups with matched age and smoking status; 162 subjects (mean age, 58 years) with risk (CTGA, n = 85) and reference (TCAG, n = 77) diplotypes replicated through genomewide association study underwent chest CT for quantitative analysis of lungs and airways. We analyzed the measures in both the risk and reference groups using a 2-sample t test. RESULTS:Subjects with the risk CTGA diplotype had significantly higher total lung volume and emphysema index than the reference TCAG diplotype (P = 0.04). Mean lung density was significantly lower (P < 0.05) in the risk group. However, in the analysis of airways, wall area, luminal area, wall and lumen area ratio, and mean lung density on expiratory and inspiratory phases, no significant differences between the 2 groups were seen. CONCLUSIONS:There is a strong relationship between CT quantitative analysis and the COPD candidate gene. Furthermore, the CTGA diplotype was associated with emphysema among the phenotypes of COPD.