In a disorder called gyrate atrophy, cells in the retina begin to degenerate in late adolescence, causing night blindness that progresses to total blindness. The cause is a mutation in the gene that encodes an enzyme, ornithine aminotransferase (OAT). Researchers sequenced the OAT gene for five patients, with the following results:

Patient ........................... Mutation
A ........................ A change in codon 209 of UAU to UAA
B ........................ A change in codon 299 of UAC to UAG
C ........................ A change in codon 426 of CGA to UGA
D ........................ A two-nucleotide deletion at codons 64 and 65 that
                             results in a UGA codon at position 79
E ........................ Exon 6, including 1071 nucleotides, is entirely deleted

a. Which patient(s) have a frameshift mutation?

b. How many amino acids is patient E missing?

c. Which patient(s) will produce a shortened protein?