Yes, the base-change specificity can account for this mutation.
Original: Ile-Leu-His-Gln
Mutant: Ile-Pro-His-Gln
Mutation of the double-stranded deoxyribonucleic acid (DNA) sequence by either a thymine (T) to cytosine (C) transition in the coding strand or an adenine (A) to guanine (G) transition in the template strand will result in the CUN to CCN in the mRNA.
Original: leu CUN; mutant pro CCN where N is any base.