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.
- 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.
Department:
Location:
Sample type and Volume required:
4 mL blood EDTA (purple top)
Turnaround time:
3 days
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
Contacts:
Purine Research Laboratory at St Thomas'
020 7188 1266
St Thomas’ Hospital
North Wing - 4th Floor
Westminster Bridge Road
London SE1 7EH
North Wing - 4th Floor
Westminster Bridge Road
London SE1 7EH
Laboratory:
Last updated: 24/02/2023
