There are various forms of mutations that can occur in coding regions. One form is silent mutations, in which a change in nucleotides does not result in any change in amino acid after transcription and translation. There also exist nonsense mutations, where base alterations in the coding region code for a premature stop codon, producing a shorter final protein. Point mutations, or single base pair changes in the coding region, that code for different amino acids during translation, are called missense mutations. Other types of mutations include frameshift mutations such as insertions or deletions.