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| Mutation | Number of mutation (2006–2008) | Number of mutation (2009–2011) |
| D43N | 15 (7%) | 200 (93%) |
| S120(N,D) | 23 (12%) | 196 (88%) |
| S129Δ | 13 (6%) | 191 (94%) |
| T151I | 13 (6%) | 207 (94%) |
