Insertion/deletion (I/D) polymorphism of angiotensin-converting enzyme gene in steroid-resistant nephrotic syndrome for children: a genetic association study and meta-analysis

An assessment of the association of angiotensin-converting enzyme (ACE) gene insertion/deletion (I/D) polymorphism with steroid-resistant nephrotic syndrome (SRNS) risk in children is still controversial. A meta-analysis was performed to evaluate the relation between ACE gene polymorphisms and SRNS susceptibility. The relevant studies were screened from electronic database and eligible investigations were synthesized using meta-analysis methods. Seven investigations were identified for the analysis of association between ACE I/D gene polymorphism and SRNS risk in children, including five in Asians, one in Caucasians, and one in Africans. There was not a markedly positive association between D allele or DD genotype and SRNS susceptibility in Asians (OR = 1.60, p = 0.26; OR = 1.90, p = 0.38) and for Caucasian population (OR = 0.92, p = 0.86; OR = 0.27, p = 0.22). However, an association of D allele with SRNS susceptibility was observed (OR = 4.67, p = 0.003) in Africans, but not for DD genotype (OR = 6.00, p = 0.05). Interestingly, II genotype seemed to play a positive role against SRNS onset for Asians and African children (OR = 0.51, p = 0.02; OR = 0.07, p = 0.02), but not for Caucasians (OR = 0.33, p = 0.30). In conclusion, our results indicate that D allele or DD homozygous might not be a significant genetic molecular marker for the development of SRNS in Asians and Caucasian children. However, D allele seemed be associated with SRNS risk for Africans but DD genotype did not.     

Association of angiotensin I-converting enzyme gene insertion/deletion polymorphism and IgA nephropathy: a meta-analysis

BACKGROUND/AIMS: The angiotensin I-converting enzyme (ACE) gene insertion/deletion (I/D) polymorphism has been extensively examined for the association with immunoglobulin A (IgA) nephropathy (IgAN), however, conflicting results have occurred. We performed a meta-analysis to evaluate the association of ACE I/D polymorphism with IgAN in different ethnic groups. METHODS: 11 studies testing the association between ACE I/D polymorphism and IgAN susceptibility, and 9 studies testing the association of ACE I/D with IgAN progression were used in this analysis. The overall odds ratio (OR) was estimated by a fixed or random effect model. RESULTS: The overall OR for the risk of susceptibility and progression of IgAN in Asians for the DD genotype is 2.37 (95% CI 1.04-5.41) and 1.75 (95% CI 1.24-2.56). The overall OR for the D allele in Asians also showed a similar magnitude, though without statistical significance (p = 0.09, p = 0.13, respectively). In Caucasians, both the DD genotype and D allele were associated with IgAN progression (OR 1.90, 1.61, respectively), but not IgAN susceptibility (p = 0.30, p = 0.41, respectively). CONCLUSION: Our findings support the notion that ACE I/D polymorphism is associated with IgAN. Meanwhile, the role of ACE I/D polymorphism in Asians is different from that of Caucasians.     

Meta-analysis of the relationship between ACE I/D gene polymorphism and end-stage renal disease in patients with diabetic nephropathy

Aims: Diabetic nephropathy (DN) is the major cause for end‐stage renal disease (ESRD) and the pathogenesis for DN developing into ESRD is not clear at present. Results from published studies on the relationship between angiotensin‐converting enzyme (ACE) insertion/deletion (I/D) gene polymorphism and ESRD risk in DN patients are still conflicting. This meta‐analysis was performed to evaluate the association between ACE I/D gene polymorphism and ESRD risk in DN patients. Methods: Association studies were identified from the databases of PubMed, Embase and Cochrane Library on 1 October 2011, and eligible investigations were identified and synthesized using the meta‐analysis method. Results were expressed using odds ratios (OR) for dichotomous data and 95% confidence intervals (CI) were also calculated. Results: Twelve studies reporting the relation between ACE I/D gene polymorphism and ESRD risk in DN patients were identified. In overall populations, there was a notable association between D allele or DD genotype and ESRD susceptibility (D: OR = 1.32, 95% CI: 1.11–1.56, P = 0.002; DD: OR = 1.67, 95% CI: 1.25–2.21, P = 0.0004). In the sub‐group analysis according to ethnicity, D allele or DD genotype was associated with ESRD risk in Asians. In Caucasians, the association of DD genotype with ESRD risk was observed, but the D allele was not. Furthermore, ACE I/D gene polymorphism was associated with ESRD risk in patients with DN due to diabetes mellitus type 2, but the association was not found for patients with DN due to diabetes mellitus type‐1. Conclusions: Our results indicate that D allele or DD homozygous is associated with the ESRD susceptibility in DN patients. However, more investigations are required to further this association.     

Methylenetetrahydrofolate reductase (MTHFR) C677T gene polymorphism and diabetic nephropathy susceptibility in patients with type 2 diabetes mellitus

Abstract

Methylenetetrahydrofolate reductase (MTHFR) is a crucial enzyme that regulates nucleotide synthesis and DNA methylation. The MTHFR C677T gene polymorphism (rs1801133), a C?→?T transition at nucleotide 677 in exon 4, is a common gene variant of MTHFR and has been implicated in diabetic nephropathy, albeit with inconsistent results. Here, we performed a meta-analysis to assess the common effect size of this polymorphism on DN susceptibility. Case–control studies on the association of the MTHFR C677T gene polymorphism with DN risk were retrieved from databases up to August 1, 2013, and eligible studies were recruited into the meta-analysis and further analyzed. Of 132 studies, 33 were identified as suitable for this analysis. The results showed that T allele and TT genotype were distinctly associated with DN susceptibility in the overall population and Asians, and might be a risk factor in Caucasians and Africans (T allele: Overall population: p?<?0.00001, Asians: p?=?0.0002, Caucasians: p?=?0.02, Africans: p?<?0.00001; TT genotype: Overall population: p?<?0.00001, Asians: p?=?0.0003, Caucasians: p?=?0.008, Africans: p?=?0.0003). Furthermore, the analysis suggested that the CC genotype might play a protective role against DN onset in patients with type 2 diabetes for the overall population, Asians, Caucasian and Africans. However, due to the limited sample size in the African population, these results should be interpreted with care. In conclusion, the MTHFR C677T T allele or TT genotype might be a significant genetic molecular marker to determine the risk of DN in patients with type 2 diabetes and help to develop suitable disease prevention and management strategies.     

Association between Endothelial Nitric Oxide Synthase Glu298Asp Gene Polymorphism and Diabetic Nephropathy Susceptibility

The association between endothelial nitric oxide synthase (eNOS) Glu298Asp gene polymorphism and diabetic nephropathy (DN) risk is still controversial. A meta-analysis was performed to evaluate the association between eNOS Glu298Asp gene polymorphism and DN susceptibility. A predefined literature search and selection of eligible relevant studies were performed to collect data from electronic database. Eight articles were identified for the analysis of association between eNOS Glu298Asp gene polymorphism and DN risk. T allele was associated with DN susceptibility in overall populations, in Asians, and for Caucasians (overall populations, p = 0.005; Asians, p = 0.004; Caucasians, p = 0.002). Furthermore, GG genotype might play a protective role against DN onset for overall populations, Asians, Caucasians, and Africans. However, a link between eNOS Glu298Asp gene polymorphism and DN risk was not found in overall populations, Asians, Caucasians, and Brazil population. In conclusion, T allele might become a significant genetic molecular marker for the onset of DN in overall populations, in Asians, and for Caucasians. However, more studies should be performed in the future.     

Relationship between GSTM1/GSTT1 Null Genotypes and Renal Cell Carcinoma Risk: A Meta-Analysis

The results from the published studies on the relationship between GSTM1/GSTT1 null genotypes and renal cell carcinoma (RCC) risk are still conflicting. This meta-analysis was performed to evaluate the relationship between GSTM1/GSTT1 null genotypes and RCC susceptibility. Association studies were identified from the databases of PubMed, Embase, Cochrane Library, and CBM-disc (China Biological Medicine Database) on 1 February 2012, and eligible investigations from 1950 to 2012 were synthesized using meta-analysis method. Results were expressed as odds ratios (ORs) for dichotomous data, and 95% confidence intervals (CIs) were also calculated. Six studies were identified for the analysis of association between polymorphic deletion of GSTM1/GSTT1 and RCC risk. There was no association between GSTM1/GSTT1 null genotype and RCC susceptibility (GSTM1: N = 6, p-heterogeneity = 0.07, OR = 1.07, 95% CI: 0.85–1.35, p = 0.57; GSTT1: N = 6, p-heterogeneity < 0.00001, OR = 0.98, 95% CI: 0.58–1.65, p = 0.94). Interestingly, null genotype of GSTT1 was associated with RCC risk in Caucasians and Asians (Caucasians: N = 4, p-heterogeneity = 0.38, OR = 0.76, 95% CI: 0.61–0.95, p = 0.01; Asians: N = 1, OR = 2.39, 95% CI: 1.63–3.51, p < 0.00001). For the GSTM1–GSTT1 interaction analysis, the dual null genotype of GSTM1/GSTT1 was not significantly associated with RCC susceptibility (N = 4, p-heterogeneity = 0.006, OR = 1.17, 95% CI: 0.98–1.39, p = 0.09). However, the dual null genotype of GSTM1–GSTT1 was associated with RCC risk in Asians (N = 1, OR = 2.06, 95% CI: 1.36–3.13, p = 0.007). In conclusion, our study results suggest that GSTT1 null genotype is associated with the RCC susceptibility in Caucasians and Asians, and the dual null genotype of GSTM1–GSTT1 is associated with RCC risk in Asians. However, more genetic epidemiological investigations are required to further explore this relationship.     

ACE gene insertion/deletion polymorphism in childhood idiopathic nephrotic syndrome

The aim of this study was to determine the distribution of angiotensin converting enzyme (ACE) gene insertion/deletion (I/D) polymorphism, and its effects on clinical, laboratory, histological findings, treatment responses and progression to end-stage renal disease in childhood idiopathic nephrotic syndrome (NS). 227 children diagnosed with idiopathic NS were included in the study. Eighty-three of patients were steroid resistant and 77 of patients were focal segmental glomerulosclerosis. The control group was consisted of 287 unrelated healthy adult volunteers. ACE gene I/D polymorphism were analyzed by using PCR based method. In the entire group of children with NS, the frequencies of the II, ID, and DD genotypes of ACE gene were 13.7%, 38.3% and 48%, respectively. D allele frequency was higher in NS group than control group (0.67 vs. 0.56, p=0.001). Percentage of frequent relapser patients was found more frequently in ID or DD genotype (38.7%) than II genotype (15%) when only steroid sensitive patients were evaluated (p=0.045). The D-allele frequency was 0.65, 0.69 and 0.68 respectively in focal segmental glomerulosclerosis, biopsy proven minimal change and entire minimal change group (p>0.05) and 0.69 and 0.64 respectively in steroid sensitive and resistant groups (p>0.05). D allele frequency was not significantly different in patients with or without end-stage renal disease (0.64 vs. 0.67 respectively, p>0.005) when 115 patients who were at least five year follow-up were evaluated. The D allele frequency was higher in NS patients than healthy controls and DD or ID genotype was related with frequent relapses. ACE gene I/D polymorphism was not important in laboratory and histological findings and progression of the disease in children with NS.     

Association of Megsin 2093C/T, 2180C/T and C25663G gene polymorphism with the risk of IgA nephropathy

The association between megsin 2093C/T, 2180C/T and C25663G gene polymorphisms and IgA nephropathy (IgAN) risk remains unclear. We aimed to evaluate the association between megsin 2093C/T, 2180C/T and C25663G gene polymorphisms and IgAN risk by performing a meta-analysis. Eligible studies were searched according to predefined criteria by using electronic databases. Six articles were identified for the analysis of the association between megsin 2093C/T, 2180C/T and C25663G gene polymorphisms and IgAN risk. 2093C/T C allele was associated with IgAN risk in overall populations and Asians (overall populations: p?=?0.014, Asians: p?=?0.037). 2093C/T CC/TT genotype was not associated with IgAN risk in overall populations, Caucasians and Asians. 2180C/T C allele was correlated with IgAN risk in Caucasians (p?=?0.024). 2180C/T CC/TT genotype was not associated with IgAN risk in overall populations, Caucasians and Asians. C25663G gene polymorphism was not associated with IgAN onset in Asians. In conclusion, megsin 2093C/T C allele may be genetic marker for IgAN susceptibility in overall populations and Asians. 2180C/T C allele may be risk factor for IgAN onset in Caucasians. However, more studies should be performed in the future.     

ACE DD genotype: a predisposing factor for abdominal aortic aneurysm.

OBJECTIVE: To examine the role of polymorphisms in angiotensin converting enzyme (ACE, I/D) and angiotensin II receptor (AT1R, A1166C) in the development of abdominal aortic aneurysm (AAA). MATERIALS AND METHODS: We investigated 250 consecutive patients, 217 males and 33 females (median age 72, range 50-83), undergone AAA elective repair and 250 healthy controls, comparable for sex and age. ACE and AT1R polymorphisms were studied by PCR-RFLP analysis. The genotype distribution was in Hardy-Weinberg equilibrium for all polymorphisms. RESULTS: The genotype distribution and allele frequency of ACE I/D, but not AT1R A1166C polymorphism were significantly different between patients and controls (ACE I/D: p=0.0002 and p<0.0001, respectively, and AT1R A1166C: p=0.6 and p=0.4, respectively). An association between the ACE DD genotype and the predisposition to AAA was found (OR DD vs. ID+II=1.9 95% CI 1.3-2.9, p<0.0001). Multivariate analysis adjusted for age, sex, traditional vascular risk factors and other atherosclerotic localizations, showed ACE DD genotype to be independently related to the disease (OR DD vs. ID+II=2.4, 95% CI 1.3-4.2 p=0.003). CONCLUSIONS: Our findings document that ACE DD genotype represents a susceptibility factor for AAA.     

Lack of association of angiotensin II type 1 receptor A1166C gene polymorphism with the risk of end-stage renal disease

Abstract

The association between angiotensin II type 1 receptor (AT1R) A 1166C (rs5186) gene polymorphism and end-stage renal disease (ESRD) risk remains controversial. We aimed to assess the association between AT1R A1166C gene polymorphism and ESRD susceptibility by performing a meta-analysis. Eligible studies were searched according to a predefined criterion using electronic databases. Eight articles were identified for the analysis of the association between AT1R A1166C gene polymorphism and ESRD risk. A allele and AA genotype were not associated with ESRD risk in overall populations, Caucasians and Asians (overall populations: p?=?0.834 and 0.832, Caucasians: p?=?0.853 and 0.884, Asians: p?=?0.243 and 0.982). CC and AC genotype were not associated with ESRD risk in overall populations, Caucasians and Asians (overall populations: p?=?0.304 and 0.712, Caucasians: p?=?0.510 and 0.987, Asians: p?=?0.319 and 0.225). In conclusion, AT1R A1166C gene polymorphism may not be correlated with ESRD risk in overall populations, Caucasians and Asians. However, more studies should be performed in the future.     

Association of transforming growth factor-β1 polymorphisms with the risk of chronic kidney diseases

Abstract

The association of transforming growth factor-β1 (TGF-β1) polymorphisms with the risk of chronic kidney diseases (CKD) remains elusive. We aimed to perform a meta-analysis to evaluate the relationship between TGF-β1 polymorphisms and the susceptibility to CKD. Association studies were searched according to a defined criteria using electronic databases. The strength of association between TGF-β1 polymorphisms and CKD risk was evaluated by odds ratio (OR) with the corresponding 95% confidence interval (CI). Nine case–control studies were identified. T allele at the +869 T/C polymorphism was associated with a lower risk of CKD in Asians (p?=?0.003). TT genotype at the +869 T/C polymorphism was associated with a lower risk of CKD in overall populations and Asians (p?=?0.007 and <10^?4, respectively). CC genotype at the +869 T/C polymorphism was associated with the risk of CKD in Asians (p?=?0.002). T allele at the ?509 T/C polymorphism was associated with the risk of CKD in overall populations and Asians (p?=?0.044 and 0.050, respectively). TT genotype at the ?509 T/C polymorphism was associated with CKD risk in overall populations, Caucasians and Asians (p?<?10^?4, <10^?4, and <10^?4, respectively). No evidence of significant publication bias was noted. In conclusion, T allele at the +869 T/C polymorphism may be a protective factor against CKD risk in Asians. TT genotype at the +869 T/C polymorphism may be an indicator of lower risk of CKD in overall populations and Asians. CC genotype at the +869 T/C polymorphism may predict the susceptibility to CKD in Asians. T allele at the ?509 T/C polymorphism may be an indicator of CKD risk in overall populations and Asians. TT genotype at the ?509 T/C polymorphism was a risk factor for CKD onset in overall populations, Caucasians and Asians.     

Association between MCP-1 2518 A&gt;G gene polymorphism and chronic kidney disease

Monocyte chemoattractant protein-1 (MCP-1) is involved in the pathogenesis of chronic kidney diseases (CKD). MCP-1 2518 A>G gene polymorphism is associated with MCP-1 status. We performed a meta-analysis to assess the association between MCP-1 2518 A>G gene polymorphism and CKD risk. The eligible studies regarding the relationship between MCP-1 2518 A>G gene polymorphism and CKD risk were searched through electronic databases. The pooled odds ratios (ORs) and its 95% confidence intervals (CIs) were calculated by using a fixed-effects model, or in the presence of heterogeneity, a random-effects model. A total of 2415 cases and 2011 controls were recruited in our investigation. A allele/GG genotype was not associated with CKD risk in overall populations, Asians, Caucasians, and Africans. AA/AG genotype was not associated with the risk of CKD in overall populations, Asians, Caucasians, and Africans. AA genotype was associated with a lower risk of CKD in Caucasians (OR 0.816, 95% CI 0.703–0.947). AG genotype was associated with a higher risk of CKD in Caucasians (OR 1.230, 95% CI 1.042–1.452). There was no marked publication bias. In conclusion, AA genotype may be a protective factor against CKD susceptibility in Caucasians. AG genotype may be a risk factor for CKD risk in Caucasians. However, more studies are needed in the future.     

Association of angiotensinogen gene M235T polymorphism with the risk of IgA nephropathy: a meta-analysis

The association between angiotensinogen (AGT) M235T gene polymorphism and IgA nephropathy (IgAN) risk remains elusive. Our aim was to evaluate the association between AGT M235T gene polymorphism and IgAN susceptibility by performing a meta-analysis. Eligible studies were searched according to predefined criteria using electronic databases. Eight studies were identified for the analysis of the association between AGT M235T gene polymorphism and IgAN risk. M allele/MM genotype were not associated with IgAN risk in overall populations, Caucasians and Asians (overall populations: p?=?0.448 and 0.861, Caucasians: p?=?0.618 and 0.886, Asians: p?=?0.566 and 0.652). TT/MT genotype were not associated with IgAN risk in overall populations, Caucasians and Asians (overall populations: p?=?0.703 and 0.454, Caucasians: p?=?0.975 and 0.946, Asians: p?=?0.697 and 0.353). No evidence of publication bias was observed. In conclusion, AGT M235T gene polymorphism may not be correlated with IgAN susceptibility in overall populations, Caucasians and Asians. However, more studies should be performed in the future.     

ACE Gene Polymorphism in Turkish Children with Nephrotic Syndrome

Since 1990, the role of angiotensin converting enzyme (ACE) gene polymorphism in various renal and cardiac diseases is still debated. This study comprised 71 pediatric patients with nephrotic syndrome, 47 males (66%) and 24 females (34%) with a mean age of 57.4 ± 37.6 months, and a control group of 83 healthy males (59%) and 57 healthy females (41%) with a mean age of 505 ± 160.5 months. The distribution of the ACE genotype in the control group was II, 11%; ID, 53%; and DD, 36%, and the nephrotic syndrome was II, 4%; ID, 78%; and DD, 18%. Angiotensin-converting enzyme genotypes were significantly different between patients and control groups (p<0.05). The study groups consisted of 52 (73%) with steroid-sensitive nephrotic syndrome (SNSS) and 19 (27%) with steroid-resistant nephrotic syndrome (SRNS). The distribution of the ACE genotype was II, 6%; ID, 75%; and DD, 19% in the SSNS population and ID, 84% and DD, 16% in the SRNS population. No statistically significant difference was found between steroid sensitivity and ACE genotypes (p=0.5). The results show that ACE I/D polymorphism does not contribute to the steroid resistance, even though this study indicates that the presence of the I/D genotype has a much higher risk—approximately 2.8 times—of having nephrotic syndrome. Further studies with a larger number of patients are needed.     

Monocyte chemoattractant protein-1 -2518G/A gene polymorphism and the risk of nephropathy in type 2 diabetes mellitus among Asians: a meta-analysis

The association between monocyte chemoattractant protein-1 (MCP-1) -2518G/A gene polymorphism and the risk of nephropathy in type 2 diabetes mellitus (T2DM) remains controversial. A meta-analysis was conducted to assess the association of MCP-1 -2518G/A gene polymorphism with the risk of nephropathy in T2DM. Eight studies were included in our meta-analysis by searching electronic databases according to predefined criteria. No significant association between G allele, GG genotype, or AA genotype and the onset of nephropathy in T2DM was observed among Asians. GA genotype was significantly associated with nephropathy risk in T2DM among Asians (p?=?0.024). MCP-1 -2518G/A gene polymorphism was not associated with nephropathy risk in T2DM among Chinese, Koreans, and Turks. For Indians, G allele and AA genotype were not associated with nephropathy risk in T2DM, GG genotype was associated with a lower risk of nephropathy in T2DM (p?=?0.017), GA genotype was associated with the susceptibility of nephropathy in T2DM (p?=?0.029). In conclusions, GA genotype might be a risk factor for the onset of nephropathy in T2DM among Asians, particularly Indians; GG genotype seems to be a protective factor against the susceptibility of nephropathy in T2DM among Indians.     

ACE I/D gene polymorphism in primary FSGS and steroid-sensitive nephrotic syndrome

The role of angiotensin-converting enzyme (ACE) insertion/deletion (I/D) gene polymorphism in various renal disorders has been investigated. We evaluated the association between the clinical characteristics and ACE genotypes of Turkish children with primary focal segmental glomerulosclerosis (FSGS) and steroid-sensitive nephrotic syndrome (SSNS). Patients with FSGS (n=30) were classified into two groups: one with remission together with stable renal function (n=22) and the other without remission and with impaired renal function (n=8). We classified children with SSNS (n=43) that were followed for at least 4 years into two subgroups as having more frequent (n=19) and less frequent relapses (n=11). The DD genotype was more frequent in the SSNS group than that in controls (37% vs. 17%, ²=4.98, P=0.025). However, among SSNS subgroups, the frequency of the DD genotype was not different. The distribution of ACE genotype was similar among patients with FSGS and SSNS. There was no difference in the ACE I/D distribution between children with FSGS and normal controls (II 10%, ID 60%, DD 30% vs. II 13%, ID 70%, DD 17%). The frequency of the DD genotype was higher in FSGS patients with declining renal function (63%) than in those with stable renal function (18%) (P=0.031). Progressive renal impairment was significantly more frequent in patients with FSGS with the homozygous D allele compared with FSGS patients with ID and II genotypes. Our results indicate that the DD genotype may be a risk factor for the development of progressive renal impairment in children with FSGS; however, larger studies are required to confirm this.The abstract of this study was accepted as a poster for the 36th meeting of the European Society of Paediatric Nephrology, Bilbao, September 2002. This study was supported in part by a grant from the Istanbul University Research Fund (no T-849/17072000)     

Impact of ACE I/D gene polymorphism on congenital renal malformations

To investigate the role of the angiotensin converting enzyme (ACE) gene insertion/deletion (I/D) polymorphism on prevalence and progression of disease in children with chronic renal failure (CRF), we determined the ACE I/D genotype in 95 children with CRF due to renal malformations (hypo- /dysplasia, obstructive uropathy, reflux nephropathy; n=59), other congenital or hereditary diseases (n=23), or acquired glomerular disorders (n=13), who had been followed prospectively over a 2-year period. CRF progression rate was followed in each individual by linear regression analysis of estimates of glomerular filtration rate (GFR) obtained every 2 months. Actuarial renal ’survival’ analysis was performed, using a GFR loss of 10 ml/min per 1.73 m² as a cutoff point. The distribution of the ACE genotype did not differ among the disease groups. There was also no difference in ACE genotype distribution between the patients and a control group of healthy Caucasian children (n=163). Among the children with renal malformations, the 2-year renal survival was significantly lower in those with the DD genotype (61%) than in patients with ID or II genotype (89%, P<0.01). In the other disease groups, the ACE I/D genotype was not predictive of CRF progression. In a multivariate analysis of risk factors, the adverse effect of the DD genotype (risk ratio 10.2, P<0.05) was independent of and additive to those of arterial hypertension (RR 13.2, P<0.001) and gross proteinuria (RR 4.7, P<0.05). We conclude that the ACE DD genotype is a significant risk factor for children with congenital renal malformations to develop progressive CRF. The effect of the ACE polymorphism in this patient group is independent of hypertension and proteinuria. Received: 25 August 2000 / Revised: 10 December 2000 / Accepted: 15 December 2000     

Methylenetetrahydrofolate reductase C677T polymorphism and the risk of male infertility: a meta-analysis

Several molecular epidemiological studies have been conducted to examine the association between MTHFR C677T polymorphism and male infertility susceptibility, but the results remain inconsistent. To derive a more precise estimation of the relationship, a meta-analysis was performed. A total of 10 case-control studies, including 2275 cases and 1958 controls, were selected. Crude odds ratios (ORs) with 95% confidence intervals were used to assess the strength of association in the additive model, dominant model and recessive model. In the overall analysis, no significant association between the polymorphism and risk of male infertility was observed. Stratified analysis showed that significantly strong association between MTHFR C677T polymorphism and male infertility were present only in Asians (OR = 1.79 for TT vs. CC genotype; OR = 1.42 for CT/TT vs. CC genotype; OR = 1.50 for TT vs. CC/CT genotype; OR = 1.36 for T vs. C allele), but not in Caucasians. Additionally, MTHFR 677T was associated with a significant increase in the risk of azoospermia in all genetic models. No significantly increased risks of oligoasthenoteratozoospermia were found in any of the genetic models. In conclusion, this meta-analysis supports that MTHFR C677T polymorphism is capable of causing male infertility susceptibility in Asians, but not in Caucasians.     

Association of the methylenetetrahydrofolate reductase gene C677T polymorphism with the risk of male infertility: a meta-analysis

Several molecular epidemiological studies have been conducted to examine the association between methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism and male infertility susceptibility, but the results remain inconclusive. To derive a more precise estimation of the relationship, a meta-analysis was performed. In this meta-analysis, a total of 26 case–control studies including 5659 infertility cases and 5528 controls were selected to evaluate the possible association. The pooled odds ratios (ORs) with 95% confidence intervals (95% CIs) were used to assess the strength of association of C677T polymorphism with male infertility in the additive model, dominant model, recessive model and allele-frequency genetic model. In the overall analysis, the frequency of the 677T allele was significantly associated with male infertility susceptibility (OR?=?2.32, 95%CI?=?2.04–2.65 for TT vs. CC genotype; OR?=?1.09, 95%CI?=?1.00–1.19 for CT vs. CC genotype; OR?=?1.19, 95%CI?=?1.10–1.29 for CT/TT vs. CC genotype; OR?=?1.54, 95%CI?=?1.36–1.74 for TT vs. CC/TT genotype; OR?=?1.22, 95%CI?=?1.15–1.30 for T vs. C allele). A subgroup analysis of the subjects showed that significantly strong association between MTHFR C677T polymorphism and male infertility was present only in Asians, but not in Caucasians. Additionally, MTHFR C677T was associated with a significant increase in the risk of azoospermia in all genetic models. Meanwhile, no significantly increased risks of oligoasthenotertozoospermia (OAT) were found in most of the genetic models. In conclusion, this meta-analysis is in favor that the MTHFR C677T polymorphism is capable of causing male infertility susceptibility, especially in Asians and the subgroup of azoospermia.     

ACE I/D gene polymorphism predicts renal damage in congenital uropathies

We investigated angiotensin converting enzyme gene (ACE I/D) polymorphism as a risk for progressive renal damage in congenital uropathies. The ACE I/D genotype was determined in 196 Caucasian patients with congenital uropathies and 163 individuals with no clinical or sonographic evidence of any urological malformations. The study group included patients with ureteropelvic junction obstruction (n=49), primary obstructive megaureter (n=19), primary vesicoureteral reflux (VUR) (n=67), and posterior urethral valves (n=27). Thirty-four patients were excluded because of additional diseases or insufficient follow-up. There was no difference in the ACE I/D distribution between children with uropathies and normal controls (II 16%, ID 56%, DD 28% vs. II 26%, ID 50%, DD 24%). Renal lesions were found in 99 of 162 children by ultrasonography, intravenous pyelography, and nuclear scans. In these children there was significant over-representation of the DD genotype (II 11%, ID 53%, DD 36%) compared with normals (P<0.005, X²=14.9) or with patients with uropathies but no renal lesions (II 23%, ID 62%, DD 15%, P<0.005, X²=14.9). Because ACE I/D has been linked with progressive deterioration of renal function, we evaluated a subset of patients with initially normal kidneys who developed radiographic renal lesions (n=28). Among these patients there was an even greater over-representation of the DD genotype (II 0%, ID 43%, DD 57%, P<0.001, X²=22.6) compared with patients with uropathies but no radiographic lesions. Multivariate analysis revealed that the DD genotype is a risk factor for parenchymal destruction, which was independent of time of diagnosis, surgical intervention, or urinary tract infection. This finding was particularly relevant in patients with VUR who constituted the majority with initially normal kidneys who developed radiographic damage (22/28). Indeed, the odds ratio of developing parenchymal damage with VUR was significantly increased if the individual had the DD genotype (4.2, 95% confidence interval 1.4–13.0). In conclusion the ACE I/D gene polymorphism is a risk factor for renal parenchymal damage in patients with congenital urological abnormalities and appears particularly relevant in children with VUR, where it is an independent predisposing factor. Received: 3 November 1998 / Revised: 3 March 1999 / Accepted: 3 March 1999