The question is kind of confusing but from what I understand; missense mutations happen when an amino acid is changed to another amino acid. To find out more specifically, look at a codon chart trust me it helps so much lol (just search codon chart and go to images). missense mutations can also cause a premature stop codon so look for a changed amino acid and a stop codon when u look at the codon chart. maybe if u see the different pairs you can get a more specific answer. I hope this helps :)