What is DPYD?

The DPYD gene encodes the enzyme dihydropyrimidine dehydrogenase (DPD), which is essential for the breakdown of fluoropyrimidine drugs like 5-fluorouracil (5-FU), capecitabine, and tegafur. These chemotherapeutic agents are widely used in treating solid tumors, including colorectal, breast, and head and neck cancers. More than 80% of administered fluoropyrimidines are catabolized by DPD in the liver, making the gene’s function vital for drug clearance and safety.

Mutations in DPYD can reduce or completely eliminate the enzyme’s activity, leading to accumulation of toxic drug levels. This can result in adverse effects ranging from moderate gastrointestinal symptoms to life-threatening toxicities, such as severe neutropenia, mucositis, and even death.

Role of DPYD Mutation in Disease

Single nucleotide polymorphisms (SNPs) in DPYD impact enzyme function to varying degrees. Four well-established variants—c.1905+1G>A (also IVS14+1G>A), c.1679T>G, c.2846A>T, and c.1129–5923C>G (HapB3)—are linked to a significantly increased risk of severe toxicity when patients are treated with standard doses of 5-FU or its prodrugs.

Partial deficiency in DPD activity is found in about 3–5% of individuals of European descent, while complete deficiency is rare (<0.1%). Patients with reduced activity may tolerate adjusted, lower doses, while those lacking functional DPD require alternative treatment. Testing for DPYD variants before initiating chemotherapy allows clinicians to personalize dosing, reducing adverse events and improving outcomes.

About the TRUPCR® DPYD Mutation Detection Kit

The TRUPCR® DPYD Mutation Detection Kit is a CE-IVD certified assay developed for rapid and reliable identification of high-risk SNPs in the DPYD gene. The kit is designed for use with genomic DNA extracted from a range of human sample types including whole blood, bone marrow, and FFPE tissues.

The assay screens for the four most clinically significant DPYD mutations that impact DPD enzyme function:

• c.1905+1G>A (rs3918290)
• c.1679T>G (rs55886062)
• c.2846A>T (rs67376798)
• c.1129–5923C>G (rs75017182)

All PCR reagents are included, along with a positive control and internal reference targeting a non-mutated region of the gene. This ensures not only result accuracy but also confidence in the integrity of the DNA sample.

Principle and Workflow

The detection method uses allele-specific amplification through ARMS PCR technology. Fluorescent probes labeled with FAM and HEX identify the SNPs of interest, while TEXAS RED serves as an internal control.

Workflow steps include:

1. DNA Extraction: Isolate genomic DNA from whole blood, bone marrow, or FFPE tissue.
2. PCR Setup: Prepare reactions using the included mastermix, primers, and probes.
3. Amplification: Run the reaction on a compatible real-time PCR instrument.
4. Analysis: Interpret data using amplification curves, aided by RUO interpretation software (optional).

Clinical Application

DPYD genotyping has become a recommended pre-treatment screening tool across Europe to prevent severe chemotherapy-related toxicity. Identifying high-risk genotypes supports safe and effective fluoropyrimidine use by guiding dosing decisions or alternative therapy selection.

The TRUPCR® DPYD Mutation Detection Kit supports:

• Pharmacogenetic testing prior to chemotherapy
• Risk stratification of patients susceptible to 5-FU toxicity
• Personalized oncology care aligned with EU safety guidelines

Compatible with various PCR platforms and backed by internal controls, this kit empowers clinical labs to confidently perform pharmacogenomic screening and improve patient safety.