Abstract: Disclosed are a method of detecting the presence or absence of a single nucleotide polymorphism of a gene, for prediction of the risk of developing drug-induced lung injury, or for improving a therapeutic method, and a kit for carrying out the detection method. The detection method is characterized by comparing an ABCB1 gene in a biological sample with a wild-type ABCB1 gene to detect the presence or absence of a single nucleotide polymorphism in the ABCB1 gene in the biological sample, in particular, by determining the nucleotide at position 3751 of the CDS of the ABCB1 gene. The kit comprises an oligonucleotide probe which specifically binds to a single nucleotide polymorphism in an ABCB1 gene under selective binding conditions, or an oligonucleotide primer which amplifies a nucleic acid sequence comprising a single nucleotide polymorphism in an ABCB1 gene.

Abstract: Various highly sensitive detection methods, particularly improved PNA-LNA-PCR clamp methods, are provided as methods for detecting the presence or absence of a mutated gene contained in a gene pool rapidly, in a simple manner, with high accuracy, and with high sensitivity. As a step before the main step for detection, a pre-amplification step comprising allowing (1) a clamp primer consisting of PNA which hybridizes with all or part of a target site having a sequence of a wild-type gene or a sequence complementary to the wild-type gene, (2) a primer capable of amplifying a region comprising a target site having a sequence of the mutated gene, and (3) the gene pool to coexist in a reaction solution for gene amplification, and selectively amplifying the region comprising a target site of the mutated gene by a gene amplification method.