Association of vitamin D binding protein variants with chronic mucus hypersecretion in Iceland.

Background: Previous studies of vitamin D binding protein (VDBP, also known as group-specific component, Gc, encoded by the GC gene) have implicated two gene variants, GC*2 and GC*1F, as possible contributors with chronic obstructive pulmonary disease (COPD) protection and susceptibility, respectively. The objective of this study was to examine the association of VDBP to different subtypes of COPD.