In 2022, the first successful brain gene therapy to treat a debilitating disease called AADC was performed on very young children with the disease. Which of the following is true?
1) The children suffered from symptoms that caused muscle inactivity.
2) The children had a genetic alteration in a gene which coded for proteins that promote neurotransmitter production.
3) A corrected gene was delivered to brain cells in the brain region called the putamen.
4) The corrected gene delivered to the brain was packaged in a virus and inserted into the putamen.