LTK and chronic obstructive pulmonary disease: Of the identified genes, 1 (GPC2) was associated with doctor-diagnosed COPD, 10 (TESK2, AKR1A1, LMCD1, ERBB3, PSMA4, MAST2, MMP15, MRC2, BMP4, and LTK) with FEV1/FVC <0.7, and 11 (APH1A, CHI3L2, PTK7, RASGRP3, HSP90AA1, TESK2, ADAM33, COL15A1, LINGO1, LTBR, and SULT1A1) with FEV1 in protein SMR results, without contradicting the expression SMR results.