Enhanced testing of the DPYD gene

Following the recommendation of the European Medicines Agency CPIC (Clinical Pharmacogenetics Implementation Consortium), GHC Genetics laboratory has expanded testing of the DPYD gene (5-fluorouracil dosage) to test additional variants:

c.1236G>A (HapB3)

c.1679T>G (DPYD*13)

c.1905+1G>A (DPYD*2A)

c.2846A>T (p.D949V)

5-fluorouracil (5-FU) is used as a basic drug in the systemic cytostatic treatment of colorectal cancer, upper gastrointestinal tract tumors, head, neck as well as breast cancer. In relation to surgical treatment, it is used as part of adjuvant (postoperative) or palliative (inoperable tumours) chemotherapy or neoadjuvant (preoperative) chemotherapy. It is used in monotherapy, in combination therapy with supportive (leucovorin, levamisole) or adjuvant (cytostatics) drugs and in combination with radiation - radiochemotherapy. The function of dihydropyrimidine dehydrogenase, which is encoded by the DPYD gene, is important for its metabolism. Up to 9% of the Caucasian population has low levels of functional DPD enzyme and up to 0.5% of the population lacks the enzyme. Testing for DPYD is therefore recommended before starting treatment to reduce the risk of serious and life-threatening side effects. A 50% reduction in the dose of 5-fluorouracil is recommended for carriers of heterozygous variants of the DPYD gene