Time to incorporate pre-emptive NUDT15 testing before starting thiopurines in inflammatory bowel disease in Asia and beyond: a review.

The NUDT polymorphism occurs in up to 27% of the Asian and Hispanic population. The hematological toxicity occurs in up to a third of patients with this genetic variant. Given this, preemptive testing for NUDT15 variant is worthwhile and is probably more cost-effective than TPMT testing in these groups. Prevalence of NUDT15 variants is low in non-Finnish European population but NUDT15 variants have been linked to myelotoxicity along with TPMT genetic variants. NUDT15 preemptive testing should be considered in the migrant Asian population in Europe and North America and in Caucasian populations who develop myelotoxicity.