CHRNA3 and chronic obstructive pulmonary disease: Genetic polymorphisms of SERPINE2 (rs16865421), CHRNA3/5 (rs8034191 and rs1051730), and family with sequence similarity 13 member A (FAM13A) rs1903003, rs7671167, and rs1964516 are linked to COPD risk in the Caucasians [8,9,10,11].