Table 2.
Dose Recommendations used in the study
| Variant Status | Genotype | AS a | Recommendation |
|---|---|---|---|
| Noncarrier | ‐/‐ | 2 | Standard dosing |
| Simple heterozygous carriers | ‐/c.1236G>A b | 1.5 | 25%–50% Dose reduction |
| ‐/c.2846G>A | 1.5 | 50% Dose reduction | |
| ‐/c.1905+1G>A | 1 | ||
| ‐/c.1679T>G | 1 | ||
| Compound heterozygous carriers | c.1236G>A/c.2846A>T c | 1 | Avoid fluoropyrimidines |
| c.1236G>A/c.1905+1G>A | 0.5 | ||
| c.1236G>A/c.1679T>G | 0.5 | ||
| c.2846A>T/c.1905+1G>A | 0.5 | ||
| c.2846A>T/c.1679T>G | 0.5 | ||
| c.1905+1G>A/c.1679T>G | 0 | ||
| Homozygous carriers | c.1236G>A/c.1236G>A d | 1 | |
| c.2846A>T/c.2846A>T d | 1 | ||
| c.1905+1G>A/c.1905+1G>A | 0 | ||
| c.1679T>G/c.1679T>G | 0 |
Abbreviations and Symbols: AS, activity score; ‐, negative for tested variants.
a
The predicted AS, assuming nontested variants are functional with an AS of 1 per allele.
b
The c.1236G>A was added to the testing panel in 2018 as a proxy for haplotype‐B3 and the causative variant DPYD c.1129‐5923C>G.
c
Despite an AS of 1, we recommend avoiding fluoropyrimidines in c.1236G>A/c.2846A>T patients, however, no patients with this genotype were detected.
d
Despite an AS of 1, we recommend avoiding fluoropyrimidines in c.1236G>A/c.1236G>A or c.2846A>T/c.2846A>T patients, however, no patients with this genotype were detected.