Mutation Analysis of the AGXT Gene in Combined Liver-Kidney and Isolated Liver Transplanted Children for Primary Hyperoxaluria Type 1: a Single Center Experience

Introduction: Primary hyperoxaluria type I (PH1) is an autosomal recessive rare disorder, caused by mutations in the alanine:glyoxylate aminotransferase (AGXT) gene. We aimed to detect the AGXT gene mutations causing PH1 in combined liver-kidney and  isolated liver transplanted children with phenotypic characteristics of PH1.Material- Method: This study was carried out by including 6 Turkish children and their families followed by Dokuz Eylül. University Faculty of Medicine, Department of Pediatric Nephrology and diagnosed as primary hyperoxaluria with their phenotypic features. Clinical features, transplantation characteristics, and AGT catalytic activities of the cases were noted. The entire coding region including exon-intron boundaries of the AGXT gene was sequenced in patients and their family.Results: We detected six mutations PH1 causing and two minor allele polymorphism in six patients (five family) The entire patients had at least one PH1 related mutation. Patient 1 had homozygous minor allele polymorphisms Pro11Leu in exon 1 and Ile340Met in exon 10, and mutation Met195Arg in exon 5. Patient 2 had homozygous mutation c. 33_34insC in exon 1. Patient 3 was compound heterozygous for mutations Gly170Arg in exon 4 and c.846+1G>A in intron 8 and heterozygous minor allele polymorphisms Ile340Met in exon 10. Patient 4 had homozygous mutation c.823-824dupAG in exon 8. Patient 5 and 6 had homozygous mutation c.976delG in exon 10.Conclusion: Our studies emphazises the mutation  analysis of the entire coding region  instead of  targeted (exons 1, 4 and 7) mutation analysis of AGXT.