In April 2020, the European Medicines Agency (EMA) [22] recommended testing for the most common DPYD-mutations (DPYD*2A (c.1905 + 1G > A; IVS14 + 1G > A; rs3918290), DPYD*13 (c.1679T > G; rs55886062), polymorphism c.2846 A > T (rs67376798) and Haplotype B3 (HapB3) (c.1236G > A; c.1129–5923 C > G)) in patients prior to 5-FU exposition to identify DPD deficiency. The gene discussed is DPYD; the disease is dihydropyrimidine dehydrogenase deficiency.