Adenosine-to-Inosine (A-to-I) modifications were described well before the conception of epitranscriptomics. These modifications are very common in tissues and cells of the nervous system, and malfunctions in this deamination can result in a variety of different human diseases. A-to-I deamination has been shown to cause changes in the overall RNA structure or cause changes to the protein-coding mRNAs, although changes in codons and the amino acid they code for are not commonly seen. A-to-I RNA editing is described in more detail on the RNA editing page.