TPMT/NUDT15 genotyping (thiopurine toxicity panel)
- Description
- TPMT deficiency due to presence of genetic sequence variants is associated with toxicity to thiopurine drug therapies. Variants in the NUDT15 gene have also been associated with thiopurine-induced myelosuppression. The Purine Research Laboratory in Biochemical Sciences offers a thiopurine toxicity panel consisting of four TPMT sequence variants and one variant in the NUDT15 gene. Real time PCR based methods are used to genotype patients for the TPMT*3C, TPMT*3B, TPMT*2 and NUDT15*3 variants, prior to the start of thiopurine therapy.
- Clinical details
- Clinical indications for TPMT/NUDT15 genotyping: - Children and young adults with acute lymphoblastic leukaemia about to be treated with mercaptopurine. - Patients who have received a blood transfusion within the last 3 months as this may falsely raise TPMT enzyme activity. - Patients on renal failure/renal transplant/dialysis. TPMT inhibitors may accumulate in the blood of patients in renal failure. - Patients with very low Hb (Hb≤70g/L). Correlation between TPMT genotype and phenotype is poor for these patients.
- Related condition
- Testing site
- Synnovis : Reference Services : St Thomas' Hospital
- Laboratory
- Purine Research
- Sample type and volume required
- 4 mL blood EDTA (purple top)
- Special sample instructions
Thiopurine toxicity panel:
Allele c.DNA Amino acid rs number
TPMT*2 c.238G>C p.(Ala80Pro) rs1800462
TPMT*3B c.460G>A p.(Ala154Thr) rs1800460
TPMT*3C c.719A>G p.(Tyr240Cys) rs1142345
NUDT15*3 c.415C>T p.(Arg139Cys) rs766023281
- Storage and transport
- Store in fridge, ( don't freeze) to laboratory within 3 days/1st class post
- Turnaround time
- 3 days