An international collaboration of researchers from institutions including Women’s Hospital in Boston and University College London in the United Kingdom discovered differences in genetic variations between chronic obstructive pulmonary disease (COPD) patients with and without chronic bronchitis. The data help to explain why there is phenotypic heterogeneity (various forms of disease) among patients with COPD. The article, “Genetic Susceptibility for Chronic Bronchitis in Chronic Obstructive Pulmonary Disease,” was published in Respiratory Research.

By looking at the genes of patients, the researchers may be able to make some conclusions regarding proteins that may be involved in chronic bronchitis epidemiology, as all genes hold information to make proteins. Proteins encoded by the genes investigated in the report have known functions, and it may be possible to identify the proteins as new targets for treating chronic bronchitis and COPD.

All data were collected from former and current smokers from three different studies. Two studies were registered clinical trials–the completed ECLIPSE and the ongoing COPDGene–and the other was GenKOLS conducted in Bergen, Norway. Of interest were the patients’ chronic bronchitis status (defined as a chronic, phlegm-producing cough for three months over the last two years), COPD status (defined by spirometry grade), and genetic signature (evaluated using one of three different quality-controlled platforms). When making comparisons, smokers with normal spirometry were also used.

A new variation on chromosome 11p15.5 was identified among chronic bronchitis-COPD patients that was not significant to smokers with normal spirometry. Further association between COPD and alterations in the gene FAM13A was made. Interestingly, COPD patients with and without chronic bronchitis had differences in chromosome 1q23.3. While FAM13A was previously found to be altered, the locus on 11p15.5 has new been explored. Perhaps future research will give insight to its involvement in disease onset.