Table 1.
Most important genetic variants associated with thiopurine toxicity.
| Genetic variant | Functional consequence | Clinical consequence |
|---|---|---|
| TPMT*2 (rs1800462) TPMT*3C (rs1142345) TPMT*3A: contains *3B (rs1800460) and *3C (rs1142345) |
Low TMPT enzymatic activity | Risk of myelotoxicity |
| NUDT15 p.Arg139Cys or c415C>T (rs116855232) |
Low NUDT15 enzymatic activity | Risk of myelotoxicity |
| NUDT15 p.Val18_Val19insGlyVal allele | Low NUDT15 enzymatic activity | Risk of myelotoxicity |
| Class II HLA polymorphism (rs2647087) | Unclear | Risk of pancreatitis |
| ITPA 94C > A (rs1127354) |
Low enzymatic activity | Inconclusive data about increased risk of side effects |
| FTO Ala134Thr (rs79206939) |
Low enzymatic activity | Leukopenia |