Novel mutations of the AGXT gene causing primary hyperoxaluria type 1

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Title: Novel mutations of the AGXT gene causing primary hyperoxaluria type 1
Authors: Wong, PN, Wong, FKM, Mak, SK, Lo, KY, Wong, AKM, Tong, SF, Chan, YW, Lam, CW, Yuen, YP, Lai, CK, Tong, GMW
Publisher Information: Wichtig Editore srl. The Journal's web site is located at http://www.jnephrol.com/index.asp?a=current, 2012.
Publication Year: 2012
Subject Terms: Dna Mutational Analysis, Adult, Male, Transaminases - Genetics, Recurrence, Hyperoxaluria - Genetics, Kidney Calculi - Blood - Genetics, Mutation, Humans, Middle Aged, Child
Description: Background: Primary hyperoxaluria type 1 (PH1), an inherited cause of nephrolithiasis, is due to a functional defect of the liver-speciffc peroxisomal enzyme alanine:glyoxylate aminotransferase (AGT). A definitive PH1 diagnosis can be established by analyzing AGT activity in liver tissue or mutation analysis of the AGXT gene. Methods: The molecular basis of PH1 in three Chinese patients, two with adult-onset and one with childhood-onset recurrent nephrolithiasis, was established by analyzing the entire AGXT gene. Results: Three novel mutations (c2T>C, c817insAG and c844C>T) and two previously reported mutations (c33insC and 679-IVS6+2delAAgt) were identified. c2T>C converts the initiation codon from ATG to ACG, which predicts significant reduction, if not complete abolition, of protein translation. c817insAG leads to a frameshift and changes the amino acid sequence after codon 274. c844C>T changes glutamine at codon 282 to a termination codon, resulting in protein truncation. Conclusions: This is the first report describing AGXT gene mutations in Chinese patients with PH1. AGXT genotypes cannot fully explain the clinical heterogeneity of PH1, and other factors involved in disease pathogenesis remain to be identified. Our experience emphasizes the importance of excluding PH1 in patients with recurrent nephrolithiasis to avoid delay or inappropriate management.
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Document Type: Article
Language: English
Access URL: http://hdl.handle.net/10722/148553
Accession Number: edsair.dedup.wf.002..2be3d1cff7edf16e7f011f4b4d9cafba
Database: OpenAIRE
Description
Abstract:Background: Primary hyperoxaluria type 1 (PH1), an inherited cause of nephrolithiasis, is due to a functional defect of the liver-speciffc peroxisomal enzyme alanine:glyoxylate aminotransferase (AGT). A definitive PH1 diagnosis can be established by analyzing AGT activity in liver tissue or mutation analysis of the AGXT gene. Methods: The molecular basis of PH1 in three Chinese patients, two with adult-onset and one with childhood-onset recurrent nephrolithiasis, was established by analyzing the entire AGXT gene. Results: Three novel mutations (c2T>C, c817insAG and c844C>T) and two previously reported mutations (c33insC and 679-IVS6+2delAAgt) were identified. c2T>C converts the initiation codon from ATG to ACG, which predicts significant reduction, if not complete abolition, of protein translation. c817insAG leads to a frameshift and changes the amino acid sequence after codon 274. c844C>T changes glutamine at codon 282 to a termination codon, resulting in protein truncation. Conclusions: This is the first report describing AGXT gene mutations in Chinese patients with PH1. AGXT genotypes cannot fully explain the clinical heterogeneity of PH1, and other factors involved in disease pathogenesis remain to be identified. Our experience emphasizes the importance of excluding PH1 in patients with recurrent nephrolithiasis to avoid delay or inappropriate management.<br />link_to_subscribed_fulltext