Lack of association of IL8 gene polymorphisms with familial vesico-ureteral reflux

Genetic polymorphisms associated with urinary tract infection in children and adults: a systematic review and meta-analysis

INTRODUCTION

The lifetime risk of urinary tract infection is known from first-degree relative studies to be highly heritable. Associations have also been observed across the life course from pediatric urinary tract infection to recurrent urinary tract infection in adulthood, suggesting lifelong susceptibility factors. Candidate gene studies and genome-wide association studies have tested for genetic associations of urinary tract infection; however, no contemporary systematic synthesis of studies is available.

OBJECTIVE

We conducted a systematic review to identify all genetic polymorphisms tested for an association with urinary tract infection in children and adults; and to assess their strength, consistency, and risk of bias among reported associations.

DATA SOURCES AND STUDY ELIGIBILITY CRITERIA

PubMed, HuGE Navigator and Embase were searched from January 1, 2005 to November 16, 2023, using a combination of genetic and phenotype key words.

STUDY APPRAISAL AND SYNTHESIS METHODS

Fixed and random effects meta-analyses were conducted using codominant models of inheritance in metan. The interim Venice criteria were used to assess their credibility of pooled associations.

RESULTS

After removing 451 duplicates, 1821 studies reports were screened, with 106 selected for full-text review, 22 were included in the meta-analysis (7 adult studies and 15 pediatric studies). Our meta-analyses demonstrated significant pooled associations for pediatric urinary tract infection with variation in CXCR1, IL8, TGF, TLR4 and VDR; all of which have plausible roles in the pathogenesis of urinary tract infection. Our meta-analyses also demonstrated a significant pooled association for adult urinary tract infection with variation in CXCR1. All significant pooled associations were graded according to their epidemiological credibility, sample sizes, heterogeneity between studies, and risk of bias.

CONCLUSION

This systematic review provides a current synthesis of the known genetic architecture of urinary tract infection in childhood and adulthood; and should provide important information for researchers analysing future genetic association studies. Although, overall, the credibility of pooled associations was weak, the consistency of findings for rs2234671 single nucleotide polymorphisms of CXCR1 in both populations suggest a key role in the urinary tract infection pathogenesis.

Distribution of cytokine gene single nucleotide polymorphisms among a multi-ethnic Iranian population

Background:

Cytokine gene single nucleotide polymorphisms (SNPs) are widely used to study susceptibility to complex diseases and as a tool for anthropological studies.

Materials and Methods:

To investigate cytokine SNPs in an Iranian multi-ethnic population, we have investigated 10 interleukin (IL) SNPs (IL-1β (C-511T, T-31C), IL-2 (G-384T), IL-4 (C-590T), IL-6 (G-174C), IL-8 (T-251A), IL-10 (G-1082A, C-819T, C-592A) and tumor necrosis factor-alpha (TNF-α) (G-308A) in 415 Iranian subjects comprising of 6 different ethnicities. Allelic and genotypic frequencies as well as Hardy-Weinberg equilibrium (HWE) were calculated by PyPop software. Population genetic indices including observed heterozygosity (H_o), expected heterozygosity (H_e), fixation index (F_IS), the effective number of alleles (N_e) and polymorphism information content (PIC) were derived using Popgene 32 software. Multidimensional scaling (MDS) was constructed using Reynold's genetic distance obtained from the frequencies of cytokine gene polymorphism.

Results:

Genotypic distributions were consistent with the HWE assumptions, except for 3 loci (IL-4-590, IL-8-251 and IL-10-819) in Fars and 4 loci (IL-4-590, IL-6-174, IL-10-1082 and TNF-α-308) in Turks. Pairwise assessment of allelic frequencies, detected differences at the IL-4-590 locus in Gilakis versus Kurds (P = 0.028) and Lurs (P = 0.022). Mazanis and Gilakis displayed the highest (H_o= 0.50 ± 0.24) and lowest (H_o= 0.34 ± 0.16) mean observed heterozygosity, respectively.

Conclusions:

MDS analysis of our study population, in comparison with others, revealed that Iranian ethnicities except Kurds and Mazanis were tightly located within a single cluster with closest genetic affinity to Europeans.

Association study between IL-1β-511 C/T polymorphism and obsessive-compulsive disorder (OCD) in Chinese Han population

AIM

This study investigated the potential association between Obsessive-Compulsive Disorder (OCD) and a functional polymorphism of IL-1beta-511 C/T in Chinese Han population.

METHODS

The authors genotyped the IL-1beta-511 C/T of 241 OCD patients and 444 healthy control subjects and then performed a case-control association analysis.

RESULTS

No difference was found in IL-1beta-511 C/T genotypic and allelic frequencies between OCD cases and controls (chi2 = 0.501, df = 2, P = 0.78 by genotype; chi2 = 0.487, df = 1, P = 0.49 by allele).

CONCLUSION

IL-1beta-511 polymorphism may not play a major role in the genetic predisposition to OCD in Chinese Han population. Given that this is an early investigation of this gene in OCD, further studies are required to draw firm conclusions.

A case-control association study between Obsessive-Compulsive Disorder (OCD) and the MCP-1 -2518G/A polymorphism in a Chinese sample

OBJECTIVE

To investigate the association between Obsessive-Compulsive Disorder (OCD) and a functional polymorphism of MCP-1 in the Chinese Han population.

METHOD

We genotyped and performed a case-control association analysis of the MCP-1 -2518G/A polymorphism in 200 OCD patients and 294 healthy control subjects.

RESULTS

There was no significant difference in MCP-1 -2518G/A genotypic and allelic frequencies between OCD cases and controls (x² = 1.123, df = 2, P = 0.57 by genotype; x² = 0.802, df = 1, P = 0.37 by allele).

CONCLUSIONS

Our results indicated that MCP-1 -2518G/A may not play a major role in the genetic predisposition of the Chinese Han population to OCD. However, further studies using a larger number of subjects are required to obtain a clear conclusion.

Association study between MAO-A gene promoter VNTR polymorphisms and obsessive-compulsive disorder

A functional variant in the mono-amine oxidase-A (MAO-A) gene has been shown to affect neural function related to several mental disorders. Therefore, we would like to ascertain if MAO-A could be a candidate gene for obsessive-compulsive disorder (OCD). We genotyped 414 healthy subjects and 240 OCD patients and found no significant difference not only in allele frequencies in male patients (χ(2) = 0.365, DF = 1, P = 0.545, odds ratio (OR) = 1.139, confidence interval (CI) = 0.75-1.74) but also in allele frequencies (χ(2) = 0.698, DF = 1, P = 0.404, OR = 0.849, CI = 0.579-1.246) or genotypic frequencies (χ(2)=0.933, DF = 2, P = 0.627) in female patients between OCD patients and controls. Given that this is the first investigation of this gene in OCD in a Chinese Han population, further studies are required to obtain more definitive conclusions in a larger number of subjects.

A case-control study of interleukin-12 1188A/C polymorphism in obsessive-compulsive disorder in Chinese population

OBJECTIVE

Previous studies indicated that the levels of serum interleukin (IL)-12 at baseline were elevated in obsessive-compulsive disorder (OCD) patients compared with control subjects, suggesting that IL-12 maybe involved in the etiopathogenesis of OCD. Therefore, we study the relationship between 1188A/C polymorphism of IL-12(rs3212227) and OCD in Chinese Han population.

METHODS

We genotyped 194 OCD patients and 322 healthy individuals by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP), then analyzed the data using case-control association test.

RESULTS

No significant differences were found in 1188A/C genotypic and allelic frequencies between OCD cases and controls ( X 2 = 2.12, df = 2, P = 0.35 by genotype; X 2 = 0.005, df = 1, P = 0.94 by allele).

CONCLUSIONS

Our results suggested that there may be lack of an association between OCD and IL-12 1188A/C polymorphism in Chinese Han population.

Genetics of innate immunity and UTI susceptibility

A functional and well-balanced immune response is required to resist most infections. Slight dysfunctions in innate immunity can turn the 'friendly' host defense into an unpleasant foe and give rise to disease. Beneficial and destructive forces of innate immunity have been discovered in the urinary tract and mechanisms by which they influence the severity of urinary tract infections (UTIs) have been elucidated. By modifying specific aspects of the innate immune response to UTI, genetic variation either exaggerates the severity of acute pyelonephritis to include urosepsis and renal scarring or protects against symptomatic disease by suppressing innate immune signaling, as in asymptomatic bacteriuria (ABU). Different genes are polymorphic in patients prone to acute pyelonephritis or ABU, respectively, and yet discussions of UTI susceptibility in clinical practice still focus mainly on social and behavioral factors or dysfunctional voiding. Is it not time for UTIs to enter the era of molecular medicine? Defining why certain individuals are protected from UTI while others have severe, recurrent infections has long been difficult, but progress is now being made, encouraging new approaches to risk assessment and therapy in this large and important patient group, as well as revealing promising facets of 'good' versus 'bad' inflammation.

Genetic susceptibility to renal scar formation after urinary tract infection: a systematic review and meta-analysis of candidate gene polymorphisms

Identifying patients who may develop renal scarring after urinary tract infections (UTI) remains challenging, as clinical determinants explain only a portion of individual risk. An additional factor that likely affects risk is individual genetic variability. We searched for peer-reviewed articles from 1980 to December 2009 in electronic databases that reported results showing an association between gene polymorphims and renal scaring after UTI. Two independent researchers screened articles using predetermined criteria. Studies were assessed for methodological quality using an aggregate scoring system. The 18 studies ultimately included in the review had investigated 16 polymorphisms in nine genes in association with renal scarring formation after UTI. Based on the predetermined criteria for assessing the quality of the studies, 12 studies (67%) were identified as being of poor quality design. A meta-analysis of cumulative studies showed on association between renal scarring formation after UTI and the angiotensin converting enzyme insertion/deletion polymorphism [ACE I/D; recessive model for D allele; odds ratio (OR) 1.73, 95% confidence interval (CI) 1.09-2.74, P = 0.02] or transforming growth factor (TGF)-β1 c.-509 T > C polymorphism (dominant model for T allele; OR 2.24, 95% CI 1.34-3.76, P = 0.002). However, heterogeneity among studies was large, indicating a strong difference that cannot only be explained by differences in study design. The studies reviewed in this article support a modest involvement of the vasomotor and inflammatory genes in the development of renal scarring after UTIs. This review also shows that only few possible candidate genes have been investigated for an association with renal scarring, raising the hypothesis that some gene polymorphisms may exert their effects through an interaction with as yet uninvestigated factors that may be related to geographic and/or socio-economic differences.