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Expression of taste-related genes in the tongue was analysed to develop a technique for genetic diagnosis of umami taste disorders.Tissue samples were collected from healthy volunteers by scraping the foliate papillae of the tongue. Immunocytochemistry staining of gustducin, a taste-cell-specific G protein, and gene expression analysis by real-time polymerase chain reaction ofβ-actin, gustducin (GNAT3) and umami receptors (T1R1,T1R3andmGluR1) were performed. Changes in umami receptor expression following application of umami substances onto the tongue were analysed.Gustducin-positive cells were observed in the samples, indicating the presence of taste cells. Gene expression ofβ-actin,GNAT3,T1R1andT1R3was detected in all seven samples tested, while that ofmGluR1was detected in four samples. Sequence analysis by NCBI Blast showed that each polymerase chain reaction product had a 99% rate of identification of its target sequence. Stimulation of the tongue with monosodium glutamate significantly upregulated the gene expression levels ofT1R1andT1R3, indicating that this method can detect alterations in umami-related gene expression.Evaluation of the expression of the umami receptor genes,T1R1andT1R3, in the tongue may be clinically useful for objective genetic diagnosis of umami taste disorders.