Evaluation of C677T and A1298C polymorphisms of the MTHFR gene as maternal risk factors for Down syndrome and congenital heart defects.

Abnormal folate/homocysteine metabolism due to polymorphisms in genes involved in this pathway has been implicated as an etiologic factor in Down syndrome (DS). This case-control study aimed to evaluate the effect of maternal C677T and A1298C polymorphisms of the methylenetetrahydrofolate reductase (MTHFR) as risk factors for the development of DS and congenital heart defects (CHD). The distribution of these genotypic variants was similar between mothers of children with DS (n = 239) and control mothers of normal children (n = 197), but the combined genotypes 677CT or TT and 1298AA increased the risk of having offspring with DS (OR = 1.99; 95% CI 1.11-3.55). The presence of the 677T allele in case mothers resulted in a 2.07-fold higher odds of CHD in the offspring (P < 0.01). Among the 57 mothers of CHD-affected children with DS who carried the MTHFR 677CT or TT genotypes and did not have periconceptional folic acid intake, we observed a 2.26-fold increased odds (95% CI 1.25-4.09) of having any CHD-affected child with DS. Our results show that MTHFR genetic polymorphisms may be involved in the etiology of DS in our population when controlling for age. We noted a borderline significant association for the C677T polymorphism (P = 0.05). Maternal 677T allele may be associated with an increased occurrence of CHD in children with DS and we anticipate that women who carry this polymorphism would benefit from periconceptional folic acid supplementation. (c) 2009 Wiley-Liss, Inc.

The effect of ABO blood group on von Willebrand response to exercise.

Individuals of O blood group have significantly lower plasma levels of either Factor VIII (FVIII) or the von Willebrand factor (vWF). Conversely, there is accumulating evidence that elevated FVIII-vWF levels may represent an important risk factor for ischemic heart and venous thromboembolic disease. In this study, individuals exercised for 20 minutes at 10% below the first ventilatory threshold (aerobic threshold), which corresponds to 48% of maximum oxygen uptake. People with non-O blood group show higher resting and postexercise vWF levels compared with those of O blood group, as evidenced by a lower maximal heart rate. The groups were compared using the ANOVA one-way test, and a P < 0.05 was considered statistically significant. These results could change the way in which exercise training is designed for both healthy and sick individuals because O group individuals could have a more thrombogenic response to exercise.

Frequency and clinical profile of patients with polycystic kidney disease in southern Brazil.

BACKGROUND: Autosomal dominant polycystic kidney disease (ADPKD) is one of the most common genetic nephropathies, affecting one in every 800-1000 individuals in the worldwide general population and 5-10% of hemodialysis patients. Little data concerning the prevalence of ADPKD in Brazil are available. Thus, the aim of the present study was to investigate both the frequency and clinical profile of ADPKD among hemodialysis patients in south of Brazil. METHODS: This cross-sectional study consisted of patients from 24 hemodialysis centers. Patients were screened for ADPKD by clinical, laboratorial, and image examination in medical records. RESULTS: Of 1326 patients on hemodialysis in the south of Brazil that composed this study, 99 (7.5%) had polycystic kidney as primary cause for chronic renal failure. Comparisons between ADPKD and non-ADPKD patients revealed no differences regarding mean age, gender, and ethnicity. CONCLUSIONS: Our data revealed that ADPKD is prevalent among patients on hemodialysis in the south of Brazil. In addition, the clinical profile of ADPKD is similar to reported data from North America and Europe, putatively due to the similar ethnic composition mainly based on European descents.

Functional vascular endothelial growth factor -634G>C SNP is associated with proliferative diabetic retinopathy: a case-control study in a Brazilian population of European ancestry.

OBJECTIVE: The purpose of this study was to evaluate the effect of the single nucleotide polymorphism (SNP) -634G>C at the 5' regulatory region of the vascular endothelial growth factor (VEGF) in the risk of proliferative diabetic retinopathy (PDR) in the Brazilian population of European ancestry with type 2 diabetes. RESEARCH DESIGN AND METHODS: A case-control study was conducted in 501 type 2 diabetic patients of European ancestry. Patients underwent a standardized clinical, ophthalmological, and laboratory evaluation. Of these, 167 patients had PDR (case patients), and 334 were considered as control subjects (patients without PDR) for PDR. A reference population (110 individuals of European ancestry) was also evaluated. RESULTS: No evidence of association between -634G>C/VEGF and the presence of diabetic retinopathy or type 2 diabetes was observed (P > 0.05). However, CC homozygous for the SNP -634G>C was significantly more frequent in patients with PDR (37 of 167; 22.2%) than in the corresponding control group (40 of 334; 12%) in accordance with a recessive model (P = 0.003). This effect was further observed when creatinine, BMI, sex, duration of type 2 diabetes, HDL cholesterol, and systolic blood pressure were taken into account (odds ratio 1.9 [95% CI 1.01-3.79], P = 0.04). CONCLUSIONS: The presence of the allele -634C/VEGF in homozygosity is an independent risk factor for the development of PDR in type 2 diabetic patients of European ancestry.

Immunogenetics of pregnancy: role of a 14-bp deletion in the maternal HLA-G gene in primiparous pre-eclamptic Brazilian women.

The etiology and pathogenesis of pre-eclampsia (PE) involve a combination of maternal-fetal genetic and immunologic factors. The immunologic maladaptation theory of PE predicts that the maternal immune system does not tolerate the semi-allogeneic fetus. Human leukocyte antigen-G (HLA-G) is expressed in some types of immune cells as well as in the fetal-maternal interface by trophoblasts, playing an immunoregulatory role. Here we have evaluated a 14-bp deletion polymorphism in the 3'-untranslated region of exon 8 of HLA-G gene in pregnant PE women and controls. HLA-G genotypes in both control and PE women were in Hardy-Weinberg equilibrium. The healthy pregnant and PE women had similar genotype frequencies (p = 0.789). This was similarly observed when PE women were subgrouped accordingly to severity of disease (p = 0.646). However, the primiparous PE women presented a tendency toward higher frequency of the 14-bp deletion allele (0.442) compared with the primiparous healthy women (0.286), p = 0.09. Our data suggest that the maternal 14-bp deletion of HLA-G is not associated with the risk for PE but that it could affect the development of PE in primiparous women.

Plasma von Willebrand factor levels correlate with clinical outcome of severe traumatic brain injury.

Biochemical markers of cellular stress/injury have been proposed to indicate outcome after head injury. The aim of the present study was to determine whether plasma von Willebrand factor (VWF) levels correlate with primary outcome and with clinical variables in severe traumatic brain injury (TBI). Forty-four male patients, victims of severe TBI, were analyzed. Clinical outcome variables of severe TBI comprised survival and neurological assessment using the Glasgow Outcome Scale (GOS) at intensive care unit (ICU) discharge. Computerized tomography (CT) scans were analyzed according to Marshall CT classification. Three consecutive venous blood samples were taken: first sample (11.4 +/- 5.2 h after trauma, mean +/- SD), and 24 h and 7 days later. The result of mean plasma VWF concentration was significantly higher in the TBI group (273 U/dL) than in the control group (107 U/dL; p < 0.001). Severe TBI was associated with a 50% mortality rate. Nonsurvivors presented significantly higher APACHE II scores than survivors (nonsurvivors mean, 18.8; survivors mean, 12.7; p < 0.001), and also presented higher scores in Marshall CT classification (nonsurvivors mean, 4.6; survivors mean, 2.7; p < 0.05). There was a significant positive correlation between plasma levels at second plasma sampling and scores in Marshall CT classification (p < 0.05). The sensitivity of plasma VWF concentration in predicting mortality according to the cut-off of 234 U/dL was 64%, with a specificity of 68%. Therefore, VWF increases following severe TBI may be a marker of unfavorable outcome.

The catalase -262C/T promoter polymorphism and diabetic complications in Caucasians with type 2 diabetes.

Catalase is a central antioxidant enzyme constituting the primary defense against oxidative stress. In this study, we investigated whether the functional -262C/T polymorphism in the promoter of catalase gene is associated with the presence of diabetic retinopathy (DR), diabetic nephropathy (DN) and ischemic heart disease (IHD) in 520 Caucasian-Brazilians with type 2 diabetes. The -262C/T polymorphism was also examined in 100 Caucasian blood donors. Patients underwent a clinical and laboratory evaluation consisting of a questionnaire, physical examination, assessment of diabetic complications and laboratory tests. Genotype analysis was performed using the polymerase chain reaction followed by digestion with restriction enzyme. The genotype and allele frequencies of the -262C/T polymorphism in patients with type 2 diabetes were very similar to those of blood donors (T allele frequency=0.20 and 0.18, respectively). Likewise, there were no differences in either genotype or allele frequencies between type 2 diabetic patients with or without DR, DN or IHD. Thus, our results do not support the hypothesis that the -262C/T polymorphism is related to the development of DR, DN or IHD in patients with type 2 diabetes. Further studies are necessary to elucidate the role of catalase gene polymorphisms in the pathogenesis of diabetic complications.

Familial history of type 2 diabetes in patients from Southern Brazil and its influence on the clinical characteristics of this disease.

OBJECTIVE: To investigate the presence of maternal and paternal history of type 2 diabetes mellitus (DM) in relatives of 644 type 2 diabetic patients from Southern Brazil, and also to evaluate its influence on the clinical characteristics of this disease. PATIENTS AND METHODS: Familial history of type 2 DM was investigated by a questionnaire. The maternal and paternal history was investigated over two generations. Complete data sets on familial history were obtained from 396 patients. RESULTS: In general, 76.6% of the patients reported at least one first-degree affected relative. Besides, 31.6% of the patients reported a maternal history of type 2 DM and 12.6% reported a paternal history. Patients with maternal and/or paternal history presented a lower age at type 2 DM diagnosis when compared to patients without familial history. In addition, patients with only paternal history presented a higher frequency of hypertension than patients with no familial history. CONCLUSIONS: This study suggests that there is a significant maternal effect in the transmission of type 2 DM in Southern Brazil, and that most of the clinical characteristics of this disease do not differ between patients with or without familial history of type 2 DM.

Relationship of p22phox C242T polymorphism with nephropathy in type 2 diabetic patients.

BACKGROUND: In this case-control study, we investigated the possible involvement of the p22phox C242T polymorphism in the development and progression of diabetic nephropathy (DN) in 535 Caucasian Brazilians with type 2 diabetes. We also evaluated the effects of the interaction of the C242T polymorphism with smoking and hypercholesterolemia on the susceptibility to nephropathy. METHODS: Genotype analysis was performed using polymerase chain reaction (PCR) followed by digestion with restriction enzyme. Logistic regression analysis was used to control for independent risk factors associated with nephropathy. RESULTS: The genotype frequencies in patients with overt DN (CC/CT/TT: 0.36/0.47/0.17) were not significantly different from those of diabetic individuals with normoalbuminuria (0.47/0.41/0.12) or microalbuminuria (0.42/0.48/0.10) (p=0.214). Likewise, there were no differences in the T allele frequency among patients with normoalbuminuria, microalbuminuria or overt DN (0.33, 0.34 and 0.40, respectively; p=0.111). However, the T allele was found to be more frequent among smokers with overt nephropathy (macroalbuminuria and/or in dialysis) than those who had normoalbuminuria (43 vs. 32%, p=0.045). The multiple logistic regression analysis confirmed that the CT+TT genotypes were independently associated with a higher risk of having overt nephropathy among smokers [odds ratio (OR)=6.76, 95% confidence interval (95% CI) 1.83-25.02]. CONCLUSIONS: Our study shows a gene-environment interaction associated with the increased risk of DN progression in Caucasian Brazilian smokers with type 2 diabetes. Further studies should be performed to clarify whether it exists, and to what extent there is a relationship between the p22phox C242T polymorphism and DN.

Analysis of the -1185A/G von Willebrand factor (VWF) gene polymorphism in two Brazilian ethnic groups and its effect on the plasma VWF levels.

Both genetic and environmental factors influence the variation in von Willebrand factor (VWF) levels between individuals, the main genetic variable known to be involved in differences in VWF levels being the ABO blood group. The -1185A/G polymorphism in the 5'-regulatory region of VWF gene has been associated with plasma VWF levels in a normal population. The objective of our study was to examine the relationship between the -1185A/G polymorphism and plasma VWF levels in a total of 420 individuals from two Brazilian ethnic groups. The -1185A/G genotypes were identified using polymerase chain reaction (PCR) amplification of the 864-bp VWF promoter region followed by AccII restriction digestion. Allele and genotype frequencies were significantly different between Afro-Brazilians and Euro-Brazilians. The -1185A allele frequency was 62% in Afro-Brazilians and 41% in Euro-Brazilians. Although Afro-Brazilians had higher plasma VWF levels than Euro-Brazilians, the ethnic differences were not significant. No association was observed between -1185A/G genotypes and VWF plasma levels in either ethnic groups. The present data indicate that there are no ethnic differences in VWF levels. The -1185A/G polymorphism showed significantly different frequencies between Afro-Brazilians and Euro-Brazilians, but in our study, it did not appear to play a role in the determination of VWF levels.

Diabetic retinopathy in Euro-Brazilian type 2 diabetic patients: relationship with polymorphisms in the aldose reductase, the plasminogen activator inhibitor-1 and the methylenetetrahydrofolate reductase genes.

We investigated the relationship between diabetic retinopathy (DR) and three polymorphisms, C(-106)T in the aldose reductase (ALR2) gene, 4G/5G in the plasminogen activator inhibitor-1 (PAI-1) gene and C677T in the methylenetetrahydrofolate reductase (MTHFR) gene, in 210 Euro-Brazilian type 2 diabetic patients. Retinopathy was evaluated by funduscopic examination and genotype analysis was performed using the polymerase chain reaction and allele-specific restriction. Retinopathy was detected in 47% of the patients. There were no significant differences in allele or genotype distributions between patients with or without retinopathy for all polymorphisms. Thus, the three polymorphisms are not related to the presence of DR in Euro-Brazilian type 2 diabetic patients.

[Prevalence of micro and macroangiopatic chronic complications and their risk factors in the care of out patients with type 2 diabetes mellitus]. / Prevalência de complicações micro e macrovasculares e de seus fatores de risco em pacientes com diabetes melito do tipo 2 em atendimento ambulatorial.

BACKGROUND: Type 2 diabetes (DM2) has been related to the development of macroangiopatic [coronary heart disease (CHD), peripheral vascular disease (PVD) and stroke] and microangiopatic [retinopathy, nephropathy, and distal sensory neuropathy (DSN)] complications. The aims of this study were to analyze prevalence of complications in DM2 patients and to estimate their associated risk factors. METHODS: Cross-sectional study, including 927 out patients with DM2 from three medical centers in Rio Grande do Sul: Hospital de Clinicas de Porto Alegre (n = 475), Grupo Hospitalar Conceicao (n = 229) and Hospital Sao Vicente de Paula (n = 223). Of the patients 42% were male, mean age was 59 +/- 10 years and the median known duration of DM2 was 11 (5-43) years. Retinopathy was identified by direct fundoscopy; CHD by WHO questionnaire and/or abnormal ECG and/or perfusion abnormalities on myocardial scintigraphy; DSN by compatible symptoms and absent sensation on 10 g monofilament and/or tune fork; PVD by the presence of claudication and absent foot pulses; stroke by presence of sequels and history; and nephropathy by the urinary albumin excretion rate (>20 microg/min). Hypertension was defined by blood pressure (>140/90 mmHg) and/or use of antihypertensive drugs. Body mass index (BMI, kg/m2) and waist-to-hip ratio (WHR) were calculated. RESULTS: CHD was present in 36% and PVD in 33% of the patients. Among the microvascular, 37% had nephropathy (12% with macroalbuminuria); 48% retinopathy (15% proliferative retinopathy). DSN was present in 36%. Seventy three percent of the patients presented arterial hypertension. Cholesterol levels were >200 mg/dl in 64% and BMI > 30 kg/m2 in 36%. Twenty two percent of patients were smokers and 21% ex-smokers. CONCLUSION: Diabetic complications are frequent among out patients referring to general hospitals. Almost all patients presented at least one risk factor for cardiovascular disease, justifying the efforts for identification and adequate control.

Relationship of endothelial nitric oxide synthase (eNOS) gene polymorphisms with diabetic retinopathy in Caucasians with type 2 diabetes.

BACKGROUND: Nitric oxide synthesized by endothelial nitric oxide synthase (eNOS) plays a key role in the regulation of endothelial function, and controversial results regarding the association of eNOS gene polymorphisms with diabetic complications have been reported. MATERIALS AND METHODS: In this case-control study, the relationship of the -786T/C, the VNTR intron 4 a/b and the 894G/T (Glu298Asp) polymorphisms in the eNOS gene with the presence or severity of diabetic retinopathy was analyzed in 630 Caucasian-Brazilians with type 2 diabetes (434 with and 196 without diabetic retinopathy). Genotyping of eNOS polymorphisms was carried out using the PCR or PCR-RFLP method, and haplotype frequencies were estimated using a Bayesian method. RESULTS: Genotype and allele frequencies in patients with any degree of diabetic retinopathy or proliferative diabetic retinopathy were not significantly different from those of patients without this complication for all eNOS polymorphisms. Likewise, there were no differences in haplotype frequencies among diabetic patients with or without diabetic retinopathy (p values > 0.05 for all comparisons). CONCLUSION: Our findings do not support the hypothesis that the -786T/C, the VNTR intron 4 a/b and the 894G/T (Glu298Asp) polymorphisms in the eNOS gene play a role in the pathogenesis of diabetic retinopathy in type 2 diabetes.

Risk factors for hypertensive disorders of pregnancy in southern Brazil.

OBJECTIVE: The aim of the study was to identify the frequency of risk factors for hypertensive disorders in pregnancy in Southern Brazil. METHODS: The study included 161 patients with hypertensive disorders and 169 control subjects matched by age and ethnicity. The frequency of the risk factors was compared by Fisher's exact test, chi-square and Student's t test. A multivariate logistic regression analysis assessed the independent role of clinical, social and demographic factors which were associated with occurrence of the hypertensive disease in pregnancy in the univariate analysis. RESULTS: Patients enrolled in the study were predominantly Caucasian (73%) and the mean age was 29. In the multivariate analysis, the variables associated were: family history of preeclampsia (p = 0.001; OR = 3.88; 95% CI = 1.77-8.46), diabetes (p = 0.021; OR = 3.87; 95% CI = 1.22-12.27) and chronic hypertension (p = 0.002; OR = 7.05; 95% CI = 1.99-24.93). CONCLUSION: The risk factors associated with hypertensive disorders in pregnancy appear to be similar to those reported in other countries. The knowledge of the risk factors could be helpful in a prenatal care.

Association of eNOS gene polymorphisms with renal disease in Caucasians with type 2 diabetes.

AIM: In this study we investigated if the -786T>C, the VNTR intron 4 a/b and the 894G>T (Glu298Asp) polymorphisms in the eNOS gene were associated with renal disease in 617 type 2 diabetic Caucasian-Brazilians. These polymorphisms were also examined in 100 Caucasian healthy blood donors. METHODS: Genotyping of eNOS polymorphisms was performed by PCR or PCR-RFLP and haplotype frequencies were estimated using a Bayesian method. Logistic regression analysis was done to test for association of eNOS polymorphisms with susceptibility to renal involvement (microalbuminuria, macroalbuminuria or end-stage renal disease). This analysis was carried out assuming three different genetic models for the minor allele, adjusting for possible effect modifiers. RESULTS: Genotype and allele frequencies in patients with renal disease were not significantly different from those of patients with normoalbuminuria and healthy blood donors for all eNOS polymorphisms. Likewise, there were no differences in haplotype frequencies among healthy blood donors and type 2 diabetic patients with or without renal involvement (P>0.05 for all comparisons). CONCLUSION: No associations between the -786T>C, the VNTR intron 4 a/b and the 894G>T (Glu298Asp) polymorphisms in the eNOS gene and renal disease were observed in type 2 diabetic Caucasian-Brazilians.

Prevalence of 15 mitochondrial DNA mutations among type 2 diabetic patients with or without clinical characteristics of maternally inherited diabetes and deafness.

The aim of the present study is to investigate the prevalence of ten described mitochondrial DNA (mtDNA) mutations in patients with type 2 diabetes, and search for new mutations in four mtDNA genes in a subgroup of patients with characteristics of maternally inherited diabetes and deafness (MIDD). These mutations were investigated in 407 type 2 diabetic patients without characteristics of mitochondrial diabetes ('classical' type 2 diabetes group) and in 38 type 2 diabetic patients with characteristics suggestive of MIDD. Through sequencing of four mtDNA genes in MIDD patients, we selected five others potentially pathogenic mutations that were also screened in the remaining patients. Overall, the frequency of the fifteen analyzed mutations was 36.84% in the MIDD group and 2.45% in the 'classical' type 2 diabetes group (p < 0.001). In conclusion, our study reinforces the importance of mtDNA mutations in the pathogenesis of MIDD.

Risk factors for hypertensive disorders of pregnancy in southern Brazil / Fatores de risco para distúrbios hipertensivos durante a gravidez no Sul do Brasil

OBJECTIVE:The aim of the study was to identify the frequency of risk factors for hypertensive disorders in pregnancy in Southern Brazil. METHODS: The study included 161 patients with hypertensive disorders and 169 control subjects matched by age and ethnicity. The frequency of the risk factors was compared by Fisher's exact test, chi-square and Student's t test. A multivariate logistic regression analysis assessed the independent role of clinical, social and demographic factors which were associated with occurrence of the hypertensive disease in pregnancy in the univariate analysis. RESULTS: Patients enrolled in the study were predominantly Caucasian (73 percent) and the mean age was 29. In the multivariate analysis, the variables associated were: family history of preeclampsia (p = 0.001; OR = 3.88; 95 percent CI = 1.77-8.46), diabetes (p = 0.021; OR = 3.87; 95 percent CI = 1.22-12.27) and chronic hypertension (p = 0.002; OR = 7.05; 95 percent CI = 1.99-24.93). CONCLUSION: The risk factors associated with hypertensive disorders in pregnancy appear to be similar to those reported in other countries. The knowledge of the risk factors could be helpful in a prenatal care.

OBJETIVO: Identificar a frequência dos fatores de risco para distúrbios hipertensivos durante a gravidez na região Sul do Brasil. MÉTODOS: O estudo incluiu 161 pacientes com distúrbios hipertensivos e 169 controles, compatíveis em idade e etnia. A frequência dos fatores de risco foi comparada a partir do teste exato de Fisher, teste qui-quadrado e teste t de Student. Uma análise logística multivariacional de regressão avaliou a influência de fatores clínicos, sociais e demográficos, associados com a ocorrência de doenças hipertensivas durante a gravidez na análise univariada. RESULTADOS: Os pacientes envolvidos no estudo eram predominantemente caucasianos (73 por cento) e a idade média foi 29 anos. Na análise multivariada as variáveis associadas foram: histórico de pré-eclâmpsia na família (p = 0,001; OR = 3,88; 95 por cento IC = 1,77-8,46), diabetes (p = 0,021; OR = 3,87; 95 por cento IC = 1,22-12,27) e hipertensão crônica (p = 0,002; OR = 7,05; 95 por cento IC = 1,99-24,93). CONCLUSÃO: Os fatores de risco associados a distúrbios hipertensivos durante a gravidez parecem ser similares àqueles relatados em outros países. O conhecimento sobre os fatores de risco pode ser útil durante o acompanhamento pré-natal.

The -106CC genotype of the aldose reductase gene is associated with an increased risk of proliferative diabetic retinopathy in Caucasian-Brazilians with type 2 diabetes.

Diabetic retinopathy is a sight-threatening chronic complication of diabetes mellitus and is the leading cause of acquired blindness in adults. The -106C>T polymorphism in the promoter region of the aldose reductase (AR) gene has been shown to be associated with the susceptibility to diabetic nephropathy in type 2 diabetes, but the findings regarding the occurrence of diabetic retinopathy are conflicting. In this case-control study, we investigated whether the -106C>T polymorphism in the AR gene is involved in the development and progression of diabetic retinopathy in 579 Brazilians with type 2 diabetes (424 Caucasian- and 155 African-Brazilians). Patients underwent a clinical and laboratory evaluation consisting of a questionnaire, physical examination, assessment of diabetic complications and laboratory tests. Genotype analysis was performed using the polymerase chain reaction followed by digestion with restriction enzyme. Logistic regression analysis was used to control for independent risk factors associated with diabetic retinopathy. There were no differences in either genotype or allele frequencies for the -106C>T polymorphism between type 2 diabetic patients with or without diabetic retinopathy, in both ethnic groups. However, the CC genotype was associated with an increased risk of having proliferative diabetic retinopathy in Caucasian-Brazilians with type 2 diabetes (odds ratio (OR)=2.04; 95% confidence interval (CI)=1.21-3.45; P=0.007), independently of other risk factors associated with this complication. Thus, our results show that the -106CC genotype (-106C>T polymorphism) in the AR gene is related to the progression of diabetic retinopathy in Caucasian-Brazilians with type 2 diabetes.

The -374A allele of the receptor for advanced glycation end products gene is associated with a decreased risk of ischemic heart disease in African-Brazilians with type 2 diabetes.

Three functional polymorphisms described in the promoter of receptor for advanced glycation end products (RAGE) gene were shown to have a marked effect on transcriptional activity. The few studies which analyzed the relationship between these three polymorphisms and the diabetic complications have shown conflicting results. In this case-control study, we evaluated the association between the -429T>C, the -374T>A and the 63bp insertion/deletion (I/D) polymorphisms in the RAGE gene, and the presence of diabetic retinopathy, diabetic nephropathy and ischemic heart disease, in 703 Brazilians with type 2 diabetes (520 Caucasian- and 183 African-Brazilians). Patients underwent a clinical and laboratory evaluation consisting of a questionnaire, physical examination, assessment of diabetic complications and blood collection. Genotype analysis was performed using the polymerase chain reaction and allele-specific restriction. Logistic regression analyses were used to examine associations between the clinical and genetic variables and the presence of diabetic complications. No association between the -429C, the -374A and the 63bp D alleles and diabetic retinopathy, diabetic nephropathy or ischemic heart disease was observed in Caucasian-Brazilians with type 2 diabetes. However, the -374A allele was associated with a decreased risk of having ischemic heart disease in African-Brazilian type 2 diabetic patients [odds ratio (OR)=0.35; 95% confidence interval (CI)=0.15-0.81; P=0.014], independently of other risk factors associated with this complication. Thus, our results show that the -374A allele (-374T>A polymorphism) in the RAGE gene is related to the susceptibility of developing ischemic heart disease in African-Brazilians with type 2 diabetes.

Prevalence of 15 mitochondrial DNA mutations among type 2 diabetic patients with or without clinical characteristics of maternally inherited diabetes and deafness / Prevalência de 15 mutações no DNA mitocondrial entre pacientes diabéticos tipo 2 com ou sem características clínicas de diabetes e surdez herdados maternalmente

The aim of the present study is to investigate the prevalence of ten described mitochondrial DNA (mtDNA) mutations in patients with type 2 diabetes, and search for new mutations in four mtDNA genes in a subgroup of patients with characteristics of maternally inherited diabetes and deafness (MIDD). These mutations were investigated in 407 type 2 diabetic patients without characteristics of mitochondrial diabetes ("classical" type 2 diabetes group) and in 38 type 2 diabetic patients with characteristics suggestive of MIDD. Through sequencing of four mtDNA genes in MIDD patients, we selected five others potentially pathogenic mutations that were also screened in the remaining patients. Overall, the frequency of the fifteen analyzed mutations was 36.84 percent in the MIDD group and 2.45 percent in the "classical" type 2 diabetes group (p < 0.001). In conclusion, our study reinforces the importance of mtDNA mutations in the pathogenesis of MIDD.

Os objetivos deste estudo foram investigar a prevalência de dez mutações conhecidas no DNA mitocondrial (mtDNA) em pacientes com diabetes tipo 2, e procurar por novas mutações em quatro genes mitocondriais em um subgrupo de pacientes com características de MIDD (Maternally Inherited Diabetes and Deafness). Estas mutações foram investigadas em 407 pacientes diabéticos tipo 2 sem características de diabetes mitocondrial (grupo de diabetes tipo 2 clássico) e em 38 pacientes com diabetes tipo 2 e com características sugestivas de MIDD. Através do seqüenciamento de quatro genes mitocondriais nos pacientes com MIDD, selecionou-se cinco outras mutações potencialmente patogênicas que também foram investigadas no restante dos pacientes. De uma forma geral, a freqüência total das 15 mutações analisadas foi de 36,8 por cento no grupo de pacientes com MIDD e de 2,4 por cento no grupo de diabetes tipo 2 clássico (p < 0,001). Em conclusão, nosso estudo reforça a importância de mutações mitocondriais na patogênese do MIDD.