Patent ID: 7807359

Claim:
A method for determining the presence or absence of mutations in a Thiopurine S-methyltransferase (TPMT) gene comprising SEQ ID NO: 1 from a nucleic acid sample from a person, said method comprising: a) amplifying one or more regions of the TPMT gene to create one or more amplified regions; b) performing three single nucleotide primer extensions using at least three extension primers to detect the identity of the nucleotide added to each of the extension primers in two reactions, wherein each reaction contains only a single labeled ddNTP, wherein the identity of the nucleotide indicates the presence of absence of a mutation in the TPMT gene, and wherein the first reaction comprises labeled ddATP to detect the presence of the G460A mutation and the absence of the A719G mutation and the second reaction comprises labeled ddGTP to detect the absence of the G238C mutation.