Oligonucleotides used in the present study.

The positions refer to the primer regions located in the TPMT reference genomic DNA (GenBank ID: NG_012137.1). HQ-654 and HQ-645 are scorpion primers specifically targeting the WT and MT TPMT*2 alleles, respectively. The stem-loop structure is marked with underlined bold letters. The position of labeled fluorescent reporter (6-FAM or CY5), the corresponding quencher (BHQ1 or BHQ2), and PCR amplification blocker (HEG) are indicated. The underlined letters in the penultimate (second to the terminal) position indicate the mismatch introduced to increase AS primer specificity according to the WASP principle. The 3′-end terminal italicized letters indicate allele-distinguishable variants.