Explain what happens when there is a mutation in a gene whereby 2 bases are deleted ?

As there are 2 bases which are deleted a frameshift will occur at the site of the mutation. This means that all other amino acids coded for by the genes after the point of mutation will be different. This is because 3 bases code for one amino acid, and if there has been a deletion of any number of bases that is not a multiple of 3 then the whole sequence of amino acids produced will be changed.