CANX and chronic obstructive pulmonary disease: CircRNA biogenesis cannot be simply explained by correlating with their linear forms expression.[50] In general, the exons generated circRNAs are usually not alternatively spliced.[28, 51] Thus, circRNA biogenesis competes with canonical mRNA isoforms.[23] CircCANX was generated from CANX pre‐mRNA and downregulated in COPD, while CANX mRNA was upregulated.