Text Box: MUTATIONAL ANALYSIS IN JAPANESE PAITENTS WITH LYSINURIC PROTEIN INTOLERANCE Shoji Yu, Noguchi A, Matsumori M, Shoji Ya, Takada G Department of Pediatrics, Akita University School of Medicine, Akita, Japan Objective: Lysinuric protein intolerance (LPI) is autosomal recessive disorder caused by defective transport of the dibasic amino acids at the basolateral membranes of epitherial cells in the renal tubules and small intestine. We examined the genomic structure of the human solute carrier family 7, member 7 (SLC7A7) responsible for LPI, and discuss the results in this congress. Here, we performed mutational analyses in Japanese LPI patients. Methods: We investigated twelve Japanese patients with LPI from nine unrelated families. Their genomic DNA and cDNA were extracted from peripheral leukocytes or cultured lymphoblasts. All exons were amplified using primers located in introns, and performed automated sequencing. We also performed a haplotype analysis of LPI patients and their families with microsatellite markers and four single nucleotide polymorphisms (SNPs) in the coding region. Results & Conclusion: Four disease-causing mutations (a nonsense mutation, a missense mutations, and two splicing mutations) were identified. The mutations identified in Japanese LPI patients were different from those of Caucasian, indicating the molecular heterogeneity in the SLC7A7 gene. According to the haplotype analysis of the nonsense mutation that was found in eleven Japanese patients, a genetic founder effect was suggested in a northern part of Japan. Identification of the genomic structure of SLC7A7 will facilitate heterozygote screening in families with LPI and help physicians to conduct genetic counseling. 2014