Modification of primers for GRHPR genotyping: avoiding allele dropout by single nucleotide polymorphisms and homology sequence

Ethnic differences in GRHPR mutations in patients with primary hyperoxaluria type 2

The objective of this study was to investigate ethnic differences in the glyoxylate reductase/hydroxypyruvate reductase (GRHPR) gene in patients with primary hyperoxaluria type 2 (PH2). GRHPR was genotyped in Japanese patients with PH2 and all GRHPR mutations described to date were reviewed in terms of geographic and ethnic association. We identified a novel mutation, a two-nucleotide deletion (c.248_249delTG) in exon 3 creating a premature 'stop' at codon 91. Also, we found that the c.864_865delTG mutation was associated with the rs35891798 single-nucleotide polymorphism. The allelic frequencies of the c.103delG, c.494G>A, c.403_404+2 delAAGT, and c.864_865delTG mutations in PH2 patients were 37.8%, 15.6%, 10.0%, and 10.0%, respectively. All patients with the c.103delG mutation were Caucasian. Patients with the c.494G>A mutation and 78% (7/9) of those with the c.403_404+2 delAAGT mutation were from the Indian subcontinent, whereas those with the c.864_865delTG mutation were Chinese or Japanese. Molecular analysis of GRHPR of four Japanese PH2 patients identified a novel mutation (c.248_249delTG in exon 3). Caucasians with PH2 should be screened for the c.103delG mutation; patients from the Indian subcontinent for c.494G>A; and patients of East Asian origin (particularly) for c.864_865delTG. The prevalence of the latter mutation in PH2 patients from East Asia was 75.0%.

Association between polymorphisms in osteopontin gene (SPP1) and first episode calcium oxalate urolithiasis

We examined whether single nucleotide polymorphisms (SNPs) in SPP1 gene are associated with risk of calcium oxalate urolithiasis (COU). We genotyped nine known SNPs in SPP1 gene (rs11739060, rs28357094, rs2728127, rs11730582, rs1126772, rs9138, rs2853744, rs4754=p.Asp80Asp, and rs1126616=p.Ala236Ala). Genomic DNA from 1,026 individuals (n = 342 patients with first episode COU, and n = 684 healthy unrelated controls) was analyzed for nine SPP1 SNPs using polymerase chain reaction and melting curve analysis by means of a pair of fluorescence resonance energy transfer probes. Serum and urine osteopontin (OPN) levels were also measured using enzyme-linked immunosorbent assay kits. rs9138 AA genotype was protective (OR 0.62, 95 % CI 0.47-0.81; P = 0.004). rs28357094 TT genotype (OR 2.52, 95 % CI 1.74-3.79; P = 0.021), rs2728127 GG genotype (OR 2.64, 95 % CI 1.42-4.81; P = 0.002), and rs2853744 GG genotype (OR 1.68, 95 % CI 1.22-3.87; P = 0.003) were predisposing. None of the other examined SPP1 SNPs was associated with COU susceptibility. Subjects with protective and predisposing polymorphisms had increased and decreased serum levels of OPN, respectively. Urinary calcium/OPN ratios were higher and lower in subjects with predisposing and protective SNPs of SPP1 gene, respectively. Of 28 constructed haplotypes, 6 demonstrated significant association with COU risk. There was no sex difference in the obtained results. The SPP1 gene polymorphisms are associated with the COU susceptibility.