A 2-month-old, breastfed baby that was normal at bih begins to develop GI problems and cirrhosis of the liver. Molecular analysis indicates a normal amount of galactose-1-phosphate uridyl transferase (GALT) mRNA, but no observable enzyme activity. Which of the following would be the best possible explanation for this?: (A) Gene deletion, (B) Nonsense mutation, (C) Premature transcription termination sequence in the DNA, (D) Promoter mutation
Answer is B. Nonsense mutation