Text Box: ANALYSIS OF GENOMIC STRUCTURE IN SLC7A7 RESPONSIBLE FOR LYSINURIC PROTEIN INTOLERANCE Noguchi A, Shoji Yu, Shoji Ya, Matsumori M, 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. The metabolic defect leads to brain dysfunction caused by hyperammonemia with a functional impairment of the urea cycle. Recently, several mutations in the human solute carrier family 7,member 7 (SLC7A7), were proven to be responsible for LPI. In the present study, we analyzed the genomic structure of SLC7A7 to establish a more convenient genetic diagnosis for LPI. Methods: Genomic DNA were extracted from human peripheral leukocytes, and amplified into six different fragments, using PCR with SLC7A7-specific primers. Direct sequencing was performed on the PCR products. Results: The location and sequence of exon/intron boundaries were determined by sequence alignments of the SLC7A7 cDNA, according to GenBank database accession number AF092032. This gene contained eleven exons and ten intrtons. All of the 5$B%f (B donor and 3$B%f (B acceptor splice sites at each exon/intron junction conformed to the GT-AG rule. Four single nucleotide polymorphisms (SNPs) in the coding region of SLC7A7, and CA repeat in intron 8 were also identified, being useful for haplotype analysis of LPI patients. In addition, we also identified alternative RNA splicing of exon 2 in human peripheral blood leukocytes, cultured lymphoblasts, and fibroblasts. Conclusions: We analyzed genomic structure of SLC7A7 to establish a more convenient genetic diagnosis for LPI. To determine the physiological significance of the alternative splicing, further analysis is needed. 2013