The right answer is The TAT codon (UAU for RNA) codes for tyrosine (an amino acid) whereas the TAG (UAG for RNA) codon is a stop codon.
Yes, the person will become diabetic because the subject has been mutated nonsense.
So, there was a nonsense mutation (conversion of an amino acid codon to a stop codon). Therefore, the synthesis of insulin will be impossible because the first codon is a premature stop codon, so there will be no insulin and a development of insulin-dependent diabetes.