Synonymous SNP rs2303296 in ITSN2 was the second strongest signal of association (OR = 0.45, P = 2.31×10−4) and had previously shown weak evidence of association with FEV1 (P = 0.02) [5] but was not near to any previously identified genome-wide significant associations with lung function and has not shown evidence of association with COPD [9]. Here, ITSN2 is linked to chronic obstructive pulmonary disease.