FAM13A and chronic obstructive pulmonary disease: However, although many of these variants have previously shown association with COPD risk (TNS1, RARB, FAM13A, GSTCD, HHIP, HTR4, ADAM19, AGER, GPR126, C10orf11, THSD4),29–33 we have shown that they are not associated with change in FEV1 or FEV1/FVC over time in our cohorts.