Selection of notable mutations, ordered in a standard table of the genetic code of amino acids.
As can be seen, clinically important missense mutations generally change the properties of the coded amino acid residue between being basic, acidic, polar or nonpolar, while nonsense mutations result in a stop codon.
In the case of cancers, mutations cause aggravation of the conditions by impairing tumor suppressors or activating oncogenes.
Every U (uracil) in the mRNA corresponds to a T (thymine) in the original DNA. Therefore, mutations are often noted using T rather than U.
Source: Mikael Häggström