Association study of DGKH gene polymorphisms with calcium oxalate stone in Chinese population

Distribution of APOE gene polymorphism in the Chinese Uyghur children & its association with urolithiasis

BACKGROUND & OBJECTIVES

This study was to survey the apolipoprotein E (APOE) gene polymorphism distribution among Chinese Uyghur children and to explore the relationship between APOE gene polymorphism and the occurrence of urolithiasis.

METHODS

A total of 144 Uyghur children with urolithiasis and 274 without the history of urolithiasis were enrolled in this study. Venous blood samples were collected from all participants, and APOE genotyping, derived from rs429358 and rs7412, was performed using Sanger sequencing.

RESULTS

Among the 418 children, the most prevalent genotype was E3/3, accounting for 71.3 per cent in the urolithiasis group and 71.4 per cent in the control group, followed by E3/4 and E2/3. Higher frequencies of the ɛ2 and ɛ4 alleles and lower frequencies of the ɛ3 allele were observed in the test group, and the unusual allele ɛ1 was also found in them. However, there were no significant differences between cases and controls at both rs429358 and rs7412 genotype and allele frequencies [odds ratio (OR)=0.98, 95% confidence interval (CI): 0.57-1.67; 0.98 (0.59-1.63); 1.43 (0.75-2.74) and 1.40 (0.74-2.62), respectively]. Likewise, none of significant differences was found between cases and controls at both APOE genotype and allele frequencies [OR=0.88, 95% CI: 0.51-1.53; 0.74 (0.33-1.64); 1.10 (0.73-1.66); 1.13 (0.76-1.67) and 1.14 (0.76-1.70), respectively].

INTERPRETATION & CONCLUSIONS

The present study does not support any association between APOE genotyping and urolithiasis in Uyghur children.

Novel Risk Loci Identified in a Genome-Wide Association Study of Urolithiasis in a Japanese Population

BACKGROUND

A family history of urolithiasis is associated with a more than doubling of urolithiasis risk, and a twin study estimating 56% heritability of the condition suggests a pivotal role for host genetic factors. However, previous genome-wide association studies (GWAS) have identified only six risk-related loci.

METHODS

To identify novel urolithiasis-related loci in the Japanese population, we performed a large-scale GWAS of 11,130 cases and 187,639 controls, followed by a replication analysis of 2289 cases and 3817 controls. Diagnosis of urolithiasis was confirmed either by a clinician or using medical records or self-report. We also assessed the association of urolithiasis loci with 16 quantitative traits, including metabolic, kidney-related, and electrolyte traits (such as body mass index, lipid storage, eGFR, serum uric acid, and serum calcium), using up to 160,000 samples from BioBank Japan.

RESULTS

The analysis identified 14 significant loci, including nine novel loci. Ten regions showed a significant association with at least one quantitative trait, including metabolic, kidney-related, and electrolyte traits, suggesting a common genetic basis for urolithiasis and these quantitative traits. Four novel loci were related to metabolic traits, obesity, hypertriglyceridemia, or hyperuricemia. The remaining ten loci were associated with kidney- or electrolyte-related traits; these may affect crystallization. Weighted genetic risk score analysis indicated that the highest risk group (top 20%) showed an odds ratio of 1.71 (95% confidence interval, 1.42 to 2.06) - 2.13 (95% confidence interval, 2.00 to 2.27) compared with the reference group (bottom 20%).

CONCLUSIONS

Our findings provide evidence that host genetic factors related to regulation of metabolic and crystallization pathways contribute to the development of urolithiasis.

Genetic Risk Factors for Idiopathic Urolithiasis: A Systematic Review of the Literature and Causal Network Analysis

CONTEXT

Urolithiasis has a high prevalence and recurrence rate. Prevention is key to patient management, but risk stratification is challenging. In particular, genetic predisposition for urinary stones is not fully understood.

OBJECTIVE

To review current evidence of potential causative genes for idiopathic urolithiasis and map their relationships to one another. This evidence is essential for future establishment of molecular targeted therapy.

EVIDENCE ACQUISITION

A systematic literature review from 2007 to 2017 was performed in accordance with the Preferred Reporting Items for Systematic Review and Meta-analyses guidelines. The search was restricted to human studies conducted as either case-control or genome-wide association studies, and published in English. We also performed a causal network analysis of candidate genes gained from the systematic review using Ingenuity Pathway Analysis (IPA).

EVIDENCE SYNTHESIS

During the systematic screening of literature, 30 papers were selected for the review. A total of 20 genes with 42 polymorphisms/variants were found to be associated with urolithiasis risk. Their functional roles were mainly categorized as stone matrix, calcium and phosphate regulation, urinary concentration and constitution, and inflammation/oxidative stress. IPA network analysis revealed that these genes connected via signaling pathways and a proinflammatory/oxidative environment.

CONCLUSIONS

This systematic review provides an updated gene list and novel causal networks for idiopathic urolithiasis risk. Although some genes such as SPP1, CASR, VDR, CLDN14, and SLC34A1 were identified by several studies and recognized by prior reviews, further investigation elucidating their roles in stone formation will be essential for future studies.

PATIENT SUMMARY

In this review, we summarized recent literature regarding genes responsible for kidney stone risk. Based on a detailed review of 30 articles and computational network analysis, we concluded that disorder of mineral regulation with local inflammation in the kidney may cause kidney stone disease.

Association Study of Reported Significant Loci at 5q35.3, 7p14.3, 13q14.1 and 16p12.3 with Urolithiasis in Chinese Han Ethnicity

In this study, we aimed to validate the association of 8 reported significant loci at 5q35.3, 7p14.3, 13q14.1 and 16p12.3 with urolithiasis in Chinese Han population. We performed case-control association analysis using 624 patients with nephrolithiasis and 1008 control subjects. We selected single-nucleotide polymorphism (SNPs) including rs12654812 and rs11746443 from 5q32.3; rs12669187 and rs1000597 from 7q14.3; rs7981733, rs4142110 and rs17646069 from 13q14.1 and rs4293393 from 16p12.3 which were previously reported to be associated with nephrolithiasis. We found none of these eight reported SNPs were significant associated with urolithiasis risk in Chinese Han population, which suggested that differences could exist in the mechanisms of calcium urolithiasis between Chinese and Japanese Ethnics. The A allele of rs12669187 was significantly correlated with increased level of serum magnesium. The C allele of rs1000597 was associated with higher levels of serum creatinine, uric acid, calcium and lower urine pH level. The T allele of rs4142110 was correlated with higher levels of serum magnesium, phosphorus, and lower AKP level. The G alleles of rs4293393 was associated with higher serum CO₂ level. The risk alleles of these SNPs were proved to be associated with the electrolytes metabolism that may result in the formation of urolithiasis.

The genetic framework for development of nephrolithiasis

Over 1%–15% of the population worldwide is affected by nephrolithiasis, which remains the most common and costly disease that urologists manage today. Identification of at-risk individuals remains a theoretical and technological challenge. The search for monogenic causes of stone disease has been largely unfruitful and a technological challenge; however, several candidate genes have been implicated in the development of nephrolithiasis. In this review, we will review current data on the genetic inheritance of stone disease, as well as investigate the evolving role of genetic analysis and counseling in the management of nephrolithiasis.