Please read the following table in Markdown format and then answer the question according to the table. Table cells in one row are seperated by '|', and different rows are seperated by '
'.

Table:
| Gene | Route of administration | Phase | Subject number | Status |
| --- | --- | --- | --- | --- |
| CFTR | Lung, via aerosol | I | 12 | Complete |
| CFTR | Lung, via aerosol | II | 38 | Complete |
| CFTR | Lung, via aerosol | II | 100 | Complete |
| FIX | Intramuscular | I | 9 | Complete |
| FIX | Hepatic artery | I | 6 | Ended |
| TNFR:Fc | Intraarticular | I | 1 | Ongoing |
| AAT | Intramuscular | I | 12 | Ongoing |
| RPE65 | Subretinal | I-II | Multiple | Several ongoing and complete |
| sFlt-1 | Subretinal | I-II | 24 | Ongoing |
| Sarcoglycan | Intramuscular | I | 10 | Ongoing |
| GAD65, GAD67 | Intracranial | I | 12 | Complete |
| AAC | Intracranial | I | 21 | Ongoing |
| CLN2 | Intracranial | I | 10 | Ongoing |
| NGF | Intracranial | I | 6 | Ongoing |
Question:
Which gene has the subject number 21?
Answer:
AAC