Table 4.
The pharmacogenetics of RA.
| Drug | Gene | Variant | Phenotype |
|---|---|---|---|
| Methotrexate | SLC19A1 (RFC-1) | G80A | Increased or unaffected efficacy |
| MTHFR | C677T | Increased toxicity | |
| MTHFR | A1298C | Controversy regarding toxicity and efficacy | |
| ATIC | C347G | Increased gastrointestinal toxicity; increased efficacy | |
| ABCB1 (MDR1) | C3435T | Controversy regarding toxicity and efficacy | |
| MTHFD1 | G1985A | Decreased efficacy | |
| SHMT1 | C1420T | Increased toxicity | |
| TYMS | 5′-UTR repeat element | Decreased efficacy | |
| Hydroxychloroquine | IL-10 | A308G | Increased efficacy |
| IL-10 | A1082G | Increased efficacy | |
| Azathioprine | TPMT | TPMT*2, *3A, *3C | Increased toxicity |
| ITPA | C94A | Increased toxicity | |
| Anti-TNF agents | TNF | G308A | Increased efficacy in most studies; effect on toxicity is controversial |
| TNF | A238G | Increased efficacy | |
| TNFRSF1B | T196G | Decreased or no effect on efficacy | |
| FCGR3A | Val158Phe | No effect on efficacy | |
| PTPRC | SNP | Increased efficacy | |
| MAPK14 | SNP | Increased efficacy of anti-TNF antibodies (infliximab, adalimumab) | |
| Rituximab | FCGR3A | Val158Phe | Increased efficacy or no effect |