Out of 5 genes, transcript levels of 1 gene (SIRT6) was decreased and the remaining 4 genes (RAD17, CDKN1C, COX10 and KLOTHO) were significantly increased in young smokers as compared to young COPD group (Figures 2A and 3B). The gene discussed is CDKN1C; the disease is chronic obstructive pulmonary disease.