In our study an influence of XRCC1 (Arg399Gln), OGG1 (Ser326Cys), XRCC3 (Thr241Met), and XRCC4 (Ile401Thr) genetic polymorphisms on DNA repair was found in COPD patients compared to controls, as shown by residual damage (Table 3). The gene discussed is XRCC1; the disease is chronic obstructive pulmonary disease.