Several studies have demonstrated an increase in TGFB1 both in the lung[50-52] and in plasma[53] in subjects with COPD, as well as a relationship between TGFB1 levels and lung function, though the relationship between these findings and the rs1800470 genotype is not entirely clear[53]. The gene discussed is TGFB1; the disease is chronic obstructive pulmonary disease.