However, it is noteworthy that ten oligonucleotide drugs have been officially approved by FDA as of January 2020 [55], which means that the technological obstacles for oligonucleotide therapeutics are being solved step by step and the development of oligonucleotide drugs targeting NNMT is still a promising method for the prevention or treatment of obesity and related T2D in the future. The gene discussed is NNMT; the disease is obesity due to melanocortin 4 receptor deficiency.