The top-10 most significantly upregulated genes were SHROOM1, STARD13, CMTM1, SHC4, RRBP1, MUC1, ARHGEF16, TEP1, TRIM3 and GPRC5C. The top-10 most significantly downregulated genes were NPHP1, CFAP206, C11orf70, CCDC113, CSE1L, FAM83B, LTV1, GMNN, SERPINB5 and AKAP14. Figure 1 shows a heatmap of all 135 significantly differentially expressed genes between COPD patients and controls, while Table E1 in online Additional file 1 presents all 135 differentially expressed genes. The gene discussed is GPRC5C; the disease is chronic obstructive pulmonary disease.