Lack of association between polymorphisms in C4b‐binding protein and atypical haemolytic uraemic syndrome in the Spanish population

Dysregulation of the alternative pathway of complement activation, caused by mutations or polymorphisms in the genes encoding factor H, membrane co‐factor protein, factor I or factor B, is associated strongly with predisposition to atypical haemolytic uraemic syndrome (aHUS). C4b‐binding protein (C4BP), a major regulator of the classical pathway of complement activation, also has capacity to regulate the alternative pathway. Interestingly, the C4BP polymorphism p.Arg240His has been associated recently with predisposition to aHUS and the risk allele His240 showed decreased capacity to regulate the alternative pathway. Identification of novel aHUS predisposition factors has important implications for diagnosis and treatment in a significant number of aHUS patients; thus, we sought to replicate these association studies in an independent cohort of aHUS patients. In this study we show that the C4BP His240 allele corresponds to the C4BP*2 allele identified previously by isoelectric focusing in heterozygosis in 1·9–3·7% of unrelated Caucasians. Crucially, we found no differences between 102 unrelated Spanish aHUS patients and 128 healthy age‐matched Spanish controls for the frequency of carriers of the His240 C4BP allele. This did not support an association between the p.Arg240His C4BP polymorphism and predisposition to aHUS in the Spanish population. In a similar study, we also failed to sustain an association between C4BP polymorphisms and predisposition to age‐related macular degeneration, another disorder which is associated strongly with polymorphisms in factor H, and is thought to involve alternative pathway dysregulation.     

Factor H gene variants in Japanese: its relation to atypical hemolytic uremic syndrome

Mutations and polymorphisms of factor H gene (FH1) are known to be closely involved in the development of atypical hemolytic uremic syndrome (aHUS). Several groups have identified disease risk mutations and polymorphisms of FH1 for the development of aHUS, and have investigated frequencies of aHUS in a number of ethnic groups. However, such studies on Japanese populations are limited. In the present study, we analyzed FH1 in Japanese aHUS patients and healthy volunteers, and examined whether those variants impacted on a tendency for the development of aHUS in Japanese populations. Similar to previous studies, we found that a high frequency of FH1 mutations, located in exon 23 of FH1, encodes short consensus repeat 20 in C-terminal end of factor H molecule in patients with aHUS (40%), but not in healthy volunteers. Interestingly, no significant differences in frequency of well-known disease risk polymorphisms for aHUS were observed between healthy volunteers and aHUS patients. Our results suggested that although FH1 mutations relates to the development of Japanese aHUS in accordance with other ethnic studies, other factor may be required for factor H polymorphism to be a risk factor of Japanese aHUS.     

Mutations in alternative pathway complement proteins in American patients with atypical hemolytic uremic syndrome

Atypical hemolytic uremic syndrome (aHUS) is characterized by acute renal failure, thrombocytopenia and microangiopathic hemolytic anemia, and occurs with an estimated incidence in the USA of 2 per 1,000,000. Disease pathogenesis is related to dysregulation of the alternative pathway (AP) of the complement cascade at the level of the cell membrane secondary to mutations in a number of complement genes including complement factor H (CFH), complement factor H‐related 5 (CFHR5), complement factor I (CFI), CD46 (MCP), complement factor B (CFB), complement component 3 (C3) and thrombomodulin (THBD). Since aHUS is rare, mutation rate data in large patient cohorts are scarce. Here we present the first cohort of American patients in whom mutation screening was completed on all genes currently implicated in aHUS. In addition to identifying a number of novel variants, we provide information on the relative frequency of mutations in these genes in an American aHUS population. Twelve percent (12%) of patients carrying disease‐associated genetic variants segregated mutations in more than one gene mandating comprehensive genetic testing in the diagnosis and management of these patients. ©2010 Wiley‐Liss, Inc.     

Factor H autoantibodies in membranoproliferative glomerulonephritis

Factor H autoantibodies are found in ∼10% of aHUS patients. Most are associated with complete deficiency of factor H related proteins 1/3 and bind to the C terminal recognition domain. MPGN, like aHUS, is characterised by complement activation. In this study we, therefore, examined the hypothesis that factor H autoantibodies are associated with MPGN. We screened sera from 16 MPGN patients and 100 normal controls using ELISA and detected strongly positive IgG factor H autoantibodies in 2 patients. One patient had type II (DDD) MPGN (male aged 24 yrs) with C3NeF and the other type I (female aged 26 yrs) with no detectable C3NeF. We identified the binding site of the autoantibodies using small SCR domain fragments in the ELISA and showed that the autoantibodies in both patients bound predominately to the N terminal complement regulatory domain of factor H. We measured CFHR 1/3 copy number using MLPA and showed that both patients had 2 copies of CFHR1 and 3. Finally, we examined the functionality of detected factor H autoantibodies using purified patient IgG and observed increased haemolysis when purified IgG from both patients was added to normal human sera prior to incubation with rabbit red blood cells. Thus, in a cohort of MPGN patients we have found a high titre of functionally significant factor H autoantibodies in two patients with MPGN. Antibody depleting therapy may have a role in such patients and we suggest that screening for factor H autoantibodies should be undertaken in all patients with MPGN.     

Factor H autoantibodies in membranoproliferative glomerulonephritis

Factor H autoantibodies are found in ~10% of aHUS patients. Most are associated with complete deficiency of factor H related proteins 1/3 and bind to the C terminal recognition domain. MPGN, like aHUS, is characterised by complement activation. In this study we, therefore, examined the hypothesis that factor H autoantibodies are associated with MPGN. We screened sera from 16 MPGN patients and 100 normal controls using ELISA and detected strongly positive IgG factor H autoantibodies in 2 patients. One patient had type II (DDD) MPGN (male aged 24 yrs) with C3NeF and the other type I (female aged 26 yrs) with no detectable C3NeF. We identified the binding site of the autoantibodies using small SCR domain fragments in the ELISA and showed that the autoantibodies in both patients bound predominately to the N terminal complement regulatory domain of factor H. We measured CFHR 1/3 copy number using MLPA and showed that both patients had 2 copies of CFHR1 and 3. Finally, we examined the functionality of detected factor H autoantibodies using purified patient IgG and observed increased haemolysis when purified IgG from both patients was added to normal human sera prior to incubation with rabbit red blood cells. Thus, in a cohort of MPGN patients we have found a high titre of functionally significant factor H autoantibodies in two patients with MPGN. Antibody depleting therapy may have a role in such patients and we suggest that screening for factor H autoantibodies should be undertaken in all patients with MPGN.     

Atypical hemolytic uremic syndrome and genetic aberrations in the complement factor H-related 5 gene

Atypical hemolytic uremic syndrome (aHUS) is a severe renal disorder that is associated with mutations in genes encoding proteins of the alternative complement pathway. Previously, we identified pathogenic variations in genes encoding complement regulators (CFH, CFI and MCP) in our aHUS cohort. In this study, we screened for mutations in the alternative pathway regulator CFHR5 in 65 aHUS patients by means of PCR on genomic DNA and sequence analysis. Potential pathogenicity of genetic alterations was determined by published data on CFHR5 variants, evolutionary conservation and in silico mutation prediction programs. Detection of serum CFHR5 was performed by western blot analysis and enzyme-linked immunosorbent assay. A potentially pathogenic sequence variation was found in CFHR5 in three patients (4.6%). All variations were located in short consensus repeats that might be involved in binding to C3b, heparin or C-reactive protein. The identified CFHR5 mutations require functional studies to determine their relevance to aHUS, but they might be candidates for an altered genetic profile predisposing to the disease.     

The clinical significance of plasma CFHR 1–5 in lupus nephropathy

A deficiency of complement factor H may lead to excessive consumption of C3 and an increase in C3b deposition, which are important pathological characteristics of lupus nephritis. Complement factor H-related proteins (CFHRs), comprising CFHR1 to CFHR5 (CFHR1–5), are members of the wider factor H/CFHR family. Their role in lupus nephritis remains unclear. In this study, we compared circulating levels of CFHR1–5 in 152 patients diagnosed with lupus nephritis and 20 unrelated healthy individuals to explore the relationship between the expression of CFHR1–5 and development of the disease. We found that plasma levels of CFHR3 and CFHR5 were higher in patients with lupus nephritis than in healthy individuals; also, CFHR3 and CFHR5 concentrations increased with increasing systemic lupus erythematosus disease activity index (SLEDAI) values (P < 0.05). Pearson's and Spearman's correlation test results confirmed that plasma CFHR3 and CFHR5 levels in lupus nephritis patients were positively correlated with proteinuria and levels of creatinine (Cr) and anti-dsDNA (correlation coefficients = 0.491–0.717, P < 0.05), while they were negatively correlated with plasma C3 levels and eGFR [correlation coefficients = –(0.706–0.788), P < 0.05]. Receiver operating characteristic (ROC) curve analysis results confirmed that plasma CFHR3 and CFHR5 levels were predictive of SLEDAI values and disease end points (area under the curve = 0.664–0.884, P < 0.05), with patients with both high CFHR3 and high CFHR5 exhibiting the shortest progression-free survival. Thus, both CFHR3 and CFHR5 are of prognostic value in lupus nephritis status.     

Haemolytic uraemic syndrome and mutations of the factor H gene: a registry-based study of German speaking countries

Background: The aetiology of atypical haemolytic uraemic syndrome (aHUS) is, in contrast to classical, Shiga-like toxin induced HUS in children, largely unknown. Deficiency of human complement factor H and familial occurrence led to identification of the factor H gene (FH1) as the susceptibility gene, but the frequency and relevance of FH1 mutations are unknown. Methods: We established a German registry for aHUS and analysed in all patients and 100 controls the complete FH1 gene by single strand confirmational polymorphism and DNA sequencing. In addition, complement C3 and factor H serum levels were assayed. Demographic data at onset of aHUS and follow up were compared for the mutation positive and negative groups. Results: Of 111 patients with aHUS (68 female, 43 male, mean age 33 years) 14% had FH1 germline mutations, including two of eight patients with familial aHUS.For each of these eight patients, both parents were tested, and we were able to trace the mutation for five cases. In the other three cases (one with the mutation 3749 C/T, one with 3200 T/C, and one with 3566+1 G/A), we could not detect the mutation in either parent, although paternity was proven by genetic fingerprinting, suggesting that these subjects have new mutations. C3 was decreased in five mutation carriers but also in two non-carriers, and factor H was decreased in none of the carriers, but elevated in six carriers and 15 non-carriers. Clinical parameters including associated medications and diseases, and outcome of aHUS and of post-aHUS kidney transplantation were similar in the mutation positive and negative groups. Conclusion: FH1 germline mutations occur with considerable frequency in patients with aHUS. Hypocomplementaemia is not regularly associated with a germline mutation, and factor H serum levels can even be elevated. Screening for FH1 mutations contributes to the classification of aHUS.     

Effects of EPHX1 and CYP3A4*22 genetic polymorphisms on carbamazepine metabolism and drug response among Tunisian epileptic patients

The aim of this study was to evaluate the impact of polymorphisms in the EPHX1 (c.416A?>?G, c.337T?>?C) and CYP3A4*22 genes involved in carbamazepine (CBZ) metabolism and pharmacoresistance among 118 Tunisian patients with epilepsy under maintenance dose of CBZ. These genetic polymorphisms were analyzed by PCR-RFLP. Associations between plasma CBZ concentration, CBZ-E concentration, maintenance doses and metabolic ratio (CBZ-E:CBZ, CBZ-D:CBZ-E) were analyzed with each polymorphism. Both variants of EPHX1 c.416A?>?G and c.337T?>?C are significantly associated with higher metabolic ratio CBZ-E:CBZ and seem to decrease the activity of the epoxide hydrolase. The CYP3A4*22 variant allele is significantly associated with lower CBZ-D:CBZ-E ratio and seems also to be associated with less activity of the cytochrome. Our data suggest that certain polymorphisms of metabolizing enzyme genes could influence inter-individual variability of CBZ metabolism.     

Common genetic variants in complement genes other than CFH, CD46 and the CFHRs are not associated with aHUS

It is well established that common genetic variants in CFH, CD46 and the CFHRs are additional risk factors for the development of aHUS. To examine the hypothesis that common variants in other complement genes have a similar effect we genotyped 501 SNPs in 47 complement genes in 94 aHUS patients from Newcastle, 126 aHUS patients from Paris, 374 UK controls and 165 French controls. We replicated the associations in CFH, CD46 and the CFHRs but found no association with any other complement gene. The strongest associations replicated in both cohorts were found for four SNPs within CD46 (p-value<10(-3)) and five SNPs within CFH (p-value<5×10(-3)). Significant replicable associations with single SNPs in CFHR2, CFHR4 and an intergenic SNP (CR1-CD46) were also found. Analysis of the Paris cohort showed that the association with CD46 SNPs was only present in those patients with complement mutations. Haplotype analysis showed at-risk and protective haplotypes in both CD46 and CFH. The CD46 haplotype was only disease-associated in those patients with mutations.     

De novo gene conversion in the RCA gene cluster (1q32) causes mutations in complement factor H associated with atypical hemolytic uremic syndrome

Many of the complement regulatory genes within the RCA cluster (1q32) have arisen through genomic duplication and the resulting high degree of sequence identity is likely to predispose to gene conversion events. The highest degree of identity is between the genes for factor H (CFH) and five factor H-related proteins--CFHL1, CFHL2, CFHL3, CFHL4, and CFHL5. CFH mutations are associated with atypical hemolytic uremic syndrome (aHUS). In the Newcastle cohort of 157 aHUS patients we have identified CFH mutations in 25 families or individuals. Eleven of these 25 independent mutations are either c.3226C>G,Q1076E; c.3572C>T,S1191L; c.3590T>C,V1197A or combined c.3572C>T,S1191L/c.3590T>C,V1197A. Sequence analysis shows that all four of these changes could have arisen as a result of gene conversion between CFH and CFHL1. Analysis of parental samples in two patients with S1191L/V1197A has shown that the changes are de novo thus providing conclusive evidence that gene conversion is the mutational mechanism in these two cases. To confirm that S1191L and V1197A are disease predisposing we examined their functional significance in three ways - analysis of the C3b/C3d binding characteristics of recombinant mutant S1191L/V1197A protein, heparin affinity chromatography and haemolytic assays of serum samples from aHUS patients carrying these changes. The results showed that these changes resulted in impaired C3b binding and a defective capacity to control complement activation on cellular surfaces. We, therefore, provide conclusive evidence that gene conversion is responsible for functionally significant CFH mutations in aHUS.     

A CR1 polymorphism associated with constitutive erythrocyte CR1 levels affects binding to C4b but not C3b

The erythrocyte type one complement receptor (E-CR1) mediates erythrocyte binding of complement-opsonized immune complexes (IC), and helps protect against random deposition of circulating IC. Two linked CR1 polymorphisms occur in binding domains, at I643T and Q981H. In Caucasians, the variant alleles (643T, 981H) are associated with low constitutive E-CR1 expression levels. This study was conducted to determine if these polymorphisms affect ligand binding, and if so, represent risk factors for the autoimmune IC disease, systemic lupus erythematosus (SLE). In an ELISA comparing relative ligand binding differences, E-CR1 from individuals homozygous for the variant residues (643TT/981HH) exhibited greater binding to C4b, but not C3b, than homozygous wild-type E-CR1. Analysis of single-binding domain CR1 constructs demonstrated that the 981H residue imparted this enhanced C4b binding. No differences were observed in the 981H allele frequency between Caucasian controls (0.170, n = 100) and SLE patients (0.130, n = 150, P = 0.133), or between African American controls (0.169, n = 71) and SLE patients (0.157, n = 67). In a subset of individuals assessed for CR1 size, excluding from this analysis those expressing at least one B allele revealed a trend for over-representation of the 981H allele in Caucasian controls (0.231 frequency, n = 26) versus SLE patients (0.139, n = 83, P = 0.089), but again no difference between African American controls (0.188, n = 24) and SLE patients (0.191, n = 34). These data suggest that the 981H residue compensates for low constitutive expression of E-CR1 in Caucasians by enhancing C4b binding. This may contribute protection against SLE.     

The role of acetaldehyde in upper digestive tract cancer in alcoholics

Chronic excessive alcohol consumption is the strongest risk factor for upper aerodigestive tract (UADT) cancer. Multiple mechanisms are involved in alcohol-associated cancer development of the UADT, including acetaldehyde (AA) effects. AA is toxic, mutagenic, and carcinogenic. Evidence of the role of AA in alcohol-associated carcinogenesis derived from genetic linkage studies in alcoholics. Polymorphism or mutation in genes coding for AA generation or detoxification enzymes are associated with increased cancer risk. It has been clearly shown in Asians that individuals carrying the acetaldehyde dehydrogenase 2*2 (ALDH2*2) allele have a significantly increased cancer risk when they consume alcohol. In Caucasians, alcohol dehydrogenase 1*1 (ADH1C*1) allele encodes for an alcohol dehydrogenase (ADH) isoenzyme, which produces 2.5 times more AA than the corresponding allele ADH1C*2. The authors found that the ADH1C*1 allele frequency and rate of homozygosity was significantly associated with an increased risk for alcohol-related cancer. AA seems to be an important factor in alcohol-associated carcinogenesis of the UADT.     

Functional characterization of two novel non-synonymous alterations in CD46 and a Q950H change in factor H found in atypical hemolytic uremic syndrome patients

Atypical hemolytic uremic syndrome (aHUS) is a disease of complement dysregulation, characterized by hemolytic anemia, thrombocytopenia and acute renal failure. Mutations in complement inhibitors are major risk factors for development of aHUS. The three aHUS patients reported in this study had several previously identified alterations in complement inhibitors; e.g. risk haplotypes in CD46 and factor H but we also identified two novel heterozygous non-synonymous CD46 alterations (p.E142Q and p.G259V). Presence of G259V caused decreased expression of the recombinant mutant CD46 compared to wild type (WT). Western blot analysis showed that the majority of the expressed G259V protein was in the precursor form, suggesting that it is processed less efficiently than WT. Low CD46 expression on the surface of the patient's neutrophils confirmed the in vitro results. Further, G259V had a substantially impaired ability to act as a cofactor to factor I, in the degradation of both C3b and C4b. The E142Q mutant showed neither decreased expression nor impaired function. Two of the patients also had a heterozygous non-synonymous alteration in factor H (p.Q950H), reported previously in aHUS but not functionally tested. This variant showed moderately impaired function in hemolytic assays, both using patient sera and recombinant proteins. The recombinant Q950H also showed a somewhat decreased expression compared to WT but the complement inhibitory function in fluid phase was normal. Taken together, we report a novel CD46 alteration showing both a decreased protein expression and substantially impaired cofactor function (G259V) and another without an effect on expression or cofactor function (E142Q). Moreover, mild consequences of a previously reported aHUS associated rare variant in factor H (Q950H) was also revealed, underlining the clear need for functional characterization of each new aHUS associated mutation.     

Intercellular adhesion molecule-1 polymorphisms in Korean patients with Behcet s disease

Intercellular adhesion molecule-1 (ICAM-1) is expressed on vascular endothelial cells and its expression increases during the inflammatory response in patients with active Behcet's disease (BD). The ICAM1 gene mutations are associated with BD in Caucasians, but clinical features of the mutation phenotype are unknown. We analyzed ICAM1 polymorphisms in Korean BD patients to determine if there was an association between particular mutations and clinical symptoms. The prevalence of ICAM1R241G and ICAM1K469E polymorphisms was determined among 197 patients with BD and 248 healthy controls using BsrG1 and BstU1 PCR-RFLP. The frequency of both genotypes ICAM1469 * K/ * E and ICAM-1469 * E/ * E was significantly higher in BD patients compared with controls (66.0% vs 52.4%, p=0.004, OR=1.28, 95% CI 1.08-1.50) and the allele frequency of ICAM1469 * E was higher in patients with skin lesions (0.41), genital ulcers (0.41), vasculitis (0.43), ocular lesions (0.41) and arthritis (0.39) than in controls (0.31). Only one heterozygote, ICAM1241G/R, was detected in BD patients but the ICAM1241 * R mutation was not found in any of the 248 healthy controls. These results show that the ICAM1 mutation is associated with BD susceptibility, and is another genetic risk factor for BD among the Korean population.     

Age-related macular degeneration and coronary heart disease: Evaluation of genetic and environmental associations

An association between coronary heart disease (CHD) and age-related macular degeneration (AMD) has long been postulated but results from epidemiological case-control studies, and genetic analyses have been ambiguous. In this study we illuminate the association between AMD and CHD with respect to genetic and environmental risk factors, age of disease onset and AMD subgroups. AMD patients (n = 1036) and age-matched control subjects (n = 412) between 68 and 95 years of age were included in the case-control study. A medical history of CHD, cerebral stroke and arterial hypertension was determined for each individual. The assessment of interacting factors included the current use of systemic medications and smoking habits. Analysis of AMD associated genetic variants included frequent polymorphisms at the complement factor H (CFH, MIM 134370) gene (rs1061170 [p.Y402H], rs800292 [p.I62V]), the complement factor H-related 3 (CFHR3, MIM 605336)/complement factor H-related 1 (CFHR1, MIM 134371) locus (rs6677604; proxy for ΔCFHR3/CFHR1; r² = 0.97) as well as the age-related maculopathy susceptibility 2 (ARMS2, MIM 611313) gene (rs10490924 [p.A69S]).Logistic regression identified a significant positive association of AMD with AMD-risk variants in CFH, ARMS2, and smoking ≥20 packs/year. A history of CHD and the current use of antihyperuricemic agents were inversely associated with the disease. Significantly fewer patients with rs6677604 nonrisk genotype A/A regularly used statins. ARMS2:p.A69S risk variant was significantly associated with exsudative AMD. AMD patients with risk variants at rs1061170 (CFH:p.Y402H) and ARMS2 and smokers (≥20 packs/year) were significantly earlier affected by AMD than those carrying the non-risk variants at each locus.Our data support three major conclusions. First, the age of AMD onset is significantly influenced by genetic and environmental risk factors. Second, in support of previous reports we also show that the ARMS2 rs10490924:T allele is significantly linked to exsudative AMD. And finally, a self-reported history of CHD was inversely associated with AMD in this study. Novel therapeutic strategies aiming at preventing the development of AMD may considerably differ from those that have been developed to treat cardiovascular disorders as both common disorders likely underlie different pathomechanisms.     

Different gene loci within the HLA-DR and TNF regions are independently associated with susceptibility and severity in Spanish rheumatoid arthritis patients

The aim of this study was to investigate whether polymorphisms in the tumor necrosis factor (TNF) and HLA-DRB1 gene regions are independently associated with rheumatoid arthritis (RA) in a population from Lugo region of northwestern Spain. RA patients (n=179) attending hospital outpatient clinics in Lugo, northwestern Spain and matched controls (n=145) were recruited. RA susceptibility in this population was predominantly associated with DRB1*0401, while erosive disease was associated with HLA-DRB1*0101 and DRB1*04. The increase in DRB1*04 was accounted for by an increase in DRB1*0404 and *0405 but not *0401 frequencies. In contrast, *0401 frequency was significantly increased in seropositive patients. The rheumatoid arthritis shared epitope (SE) was associated with increased risk for seropositive and erosive disease and this appeared to operate in a dose-dependent manner. Logistic regression analyses revealed that the TNF microsatellite markers TNFc1 and b3 were associated with RA independently of DRB1*04 and the SE. Carriage of a TNF c1 allele provided an increased risk of RA in SE-negative and SE-heterozygous individuals. TNFc1 and TNFb3 were not associated with erosive or seropositive disease. In contrast, TNF a2 was significantly associated with erosive disease which was independent of DRB1*04 and the SE. Further studies will be needed to establish why (TNFc1) polymorphism seemingly associated with low TNFalpha production, is a risk factor for RA.     

The role of glutathione transferases M1 and T1 in individual susceptibility to bladder cancer in a Tunisian population

BACKGROUND: Susceptibility to bladder cancer is thought to depend on interplay between genetic factors and environmental chemical carcinogens. AIM: This study seeks to determine the role of the glutathione transferases M1 and T1 null genotypes (GSTM1*0 and GSTT1*0) in individual susceptibility to bladder cancer in a Tunisian population. METHOD: Sixty-two patients with transitional cell carcinoma of the bladder cancer and 79 controls were examined with respect to the frequency of GSTM1 and GSTT1 null genotypes. RESULTS: The frequencies of the GSTT1 null in the total group of bladder cancer cases vs. controls did not differ statistically. The proportion of GSTM1 null genotype in patients was 63% compared to 45% in controls group (OR = 2.03; 95% CI 0.97-4.24; p = 0.04). A significantly higher incidence of GSTM1 deletion genotype was found in smokers with bladder cancer compared to the controls (65.38% vs. 45.5%). Smokers lacking the GSTM1 gene are at an approximately 2.2-fold higher risk of bladder cancer (OR= 2.23, 95% CI 1-5.15; p = 0.03). CONCLUSION: This study suggests that in Tunisian subjects the GSTM1 null genotype may be associated with an increased risk of bladder cancer. This association appears to depend upon smoking status.     

Comparison of thrombophilic gene mutations among patients experiencing recurrent miscarriage and deep vein thrombosis

PROBLEM: Inherited thrombophilia has been shown to be a risk factor for cardiovascular disease including deep venous thrombosis as well as reproductive disorders including recurrent pregnancy loss. We have previously reported three out of the 10 thrombophilic mutations studied, plasminogen activator inhibitor-1 (PAI-1) 4G/5G, factor XIII V34L, and homozygous MTHFR C667T, correlated significantly with recurrent pregnancy loss compared with controls. This study was undertaken to compare the frequencies of nine inherited thrombophilias among women with a history of recurrent pregnancy loss with individuals experiencing deep venous thrombosis and fertile controls. METHOD OF STUDY: Six hundred thirty-four participants including 550 women with a history of recurrent pregnancy loss, 43 individuals with deep vein thrombosis and 41 fertile women without a history of recurrent miscarriage. All participants had buccal swabs taken for DNA analyses of nine gene polymorphisms including factor V G1691A, factor V H1299R (R2), factor II Prothrombin G20210A, factor XIII V34L, beta-fibrinogen -455G>A, PAI-1 4G/5G, human platelet antigen 1 a/b (L33P), MTHFR C677T, MTHFR A1298C. Frequencies of thrombophilic gene polymorphisms were compared among the three populations studied. RESULTS: Individuals with a history of DVT had a significantly higher frequency of all of the polymorphisms studied compared with women experiencing a history of recurrent pregnancy loss and the fertile controls. The frequencies of mutations for V34L and PAI-1 4G/5G were significantly increased among women experiencing recurrent pregnancy loss compared with controls. The most prevalent polymorphisms were factor XIII V34L and PAI-1 4G/4G for both individuals with a history of deep vein thrombosis and recurrent pregnancy loss compared with controls. CONCLUSION: Screening for risk factors for inherited thrombophilia with only polymorphisms for factor V von Leiden, factor II prothrombin and MTHFR may be missing the more prevalent identifiers of jeopardy.