147 resultados para Gene polymorphism


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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Purpose: Considering the importance of type beta thalassaemias as hereditary syndromes of high significance in different populations of Mediterranean origin and, by extension, in the Brazilian population, the objective of the present study was to determine by PCR/DGGE the gene structures responsible for neutral polymorphisms (frameworks) observed in the human beta globin gene associated with the mutations responsible for type beta thalassaemias in a sample of the Brazilian population and, more specifically, of the population of the State of São Paulo. Patients and methods: Thirty individuals with beta thalassaemic mutations were analyzed: 22 mutations were in codon 39 (C->T), 5 in IVS1-110 (G->A), 2 in IVS1-6 (T->C) and 1 in IVS1-1 (G->A). DNA was extracted and selective amplification was performed by PCR extending from position IVS1 nt 46 to IVS2 nt 126 (474 pb). The product was then analyzed by polyacrylamide gel electrophoresis on a denaturing 10-60% urea/formamide gradient. Results: The results demonstrated that, as expected, the mutations responsible for type beta thalassaemia observed in this population are of Mediterranean origin, with 73% distribution represented by codon 39,17% by IVS1-110, 7% by IVS1-6 and 3% by IVS1-1. In turn, framework distribution seems to indicate a higher frequency of Fr 1-1 in codon 39 and IVS1-110, of Fr 1-3 in IVS1-6 and of Fr 1-2 in IVS1-1. Conclusions: These results permit us to conclude that gene amplification by PCR followed by DGGE is an appropriate method for the separation of DNA molecules that differ even by a single base change and therefore can be utilized to detect the alterations observed in the human beta globin gene. This methodology shows that, using only a pair of primers, it is possible to define the frameworks that are observed in the beta globin gene.

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Caseins comprise make up about 80% of the total protein content of milk and present polymorphism with change in the amino acid sequence. Within this abundance of proteins, kappa-casein is noteworthy, since it has been associated with differences in milk yield, composition and processing. The objective of this study was to observe the existence of polymorphism in the kappa-casein gene in female buffaloes. For this purpose, blood samples from 115 female buffaloes, collected with vacutainer by needle punctionure of the jugular vein, were used. for genomic DNA extraction was done from blood samples. The PCR-RFLP and SSCP techniques demonstrated that the studied animals were monomorphic for the kappa-casein gene. Only allele B was observed in these animals, which was present in homozygosis. Therefore, it was not possible to quantify the gene action on milk yield and its constituents. The monomorphism observed in the population studied would allow the development of a method to identify mixtures of cow and buffalo milk in mozzarella cheese production, especially because, in cattle, the kappa-casein gene is polymorphic. Copyright by the Brazilian Society of Genetics.

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The objective of the present study was to estimate the allele and genotype frequencies of the CSN3/Hinfl and LGB/HaeIII gene polymorphisms in beef cattle belonging to different genetic groups, and to determine the effects of these polymorphisms on growth and carcass traits in these animals, which are submitted to an intensive production model. Genotyping was performed on 79 Nelore, 30 Canchim (5/8 Charolais + 3/8 Zebu) and 275 crossbred cattle originating from the crosses of Simmental (n = 30) and Angus (n = 245) sires with Nelore females. Body weight, weight gain, dressing percentage, longissimus dorsi area and backfat thickness were fitted using the GLM procedure, and least square means of the genotypes were compared by the F test. The results showed that the CSN3/Hinfl and LGB/HaeIII polymorphisms did not have any effect on growth or carcass traits (p > 0.05). Copyright by the Brazilian Society of genetics.

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The Pacific white shrimp, Litopenaeus vannamei (Penaeidae), represents about 95% of all Brazilian shrimp production. The Brazilian L. vannamei foundation broodstock was made up of specimens collected from different American Pacific sites, but little information was collected on the genetic structure of the broodstock. We used the fluorescence amplified fragment length polymorphism (fAFLP) method to study the genetic diversity of L. vannamei broodstock lines 03CMF1 and 03CBF1 originally produced by breeder-shrimps imported mainly from Panama and Ecuador, although wild individuals from other localities may also have been used in producing these two lines. Our results showed a total of 93 polymorphic bands ranging from 50 to 500 bp, the mean Nei's genetic diversity calculated for the total sample was 13.4% and identity and genetic distance analyses indicated high genetic homogeneity within and between both the broodstock lineages studied which suggests that they had similar genetic structure. These results may represent an important tool for the appropriate management of L. vannamei broodstocks. Copyright by the Brazilian Society of Genetics.

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Background: Previous reports into the role of [CAG]n repeat lengths in the androgen receptor (AR) gene indicate that these may play an important part in the development and progression of breast cancer, however, knowledge regarding benign breast lesions is limited. Patients and Methods: PCR-based GeneScan analysis was used to investigate the [CAG]n repeat length at exon 1 of the AR gene in 59 benign breast lesions (27 fibroadenomas, 18 atypical hyperplasias, and 14 hyperplasias without atypia) and 54 ductal breast carcinomas. Seventy-two cancer-free women were used as a control group. In addition, [CAG]n repeats were evaluated for the presence of loss of heterozygosity (LOH) and microsatellite instability (MSI) in a subset of these samples (27 fibroadenomas, 14 hyperplasias without atypia and 22 breast carcinomas). Results: Shorter [CAG]n repeat lengths were strongly correlated with atypical hyperplasias (p=0.0209) and carcinomas (p<0.0001). LOH was found in 1/12 and 4/20 informative cases of hyperplasias without atypia and breast carcinomas, respectively. Three patients with breast carcinoma who had previously presented atypical hyperplasia showed a reduction in the [CAG]n repeat length in their carcinomas. Conclusion: Short [CAG]n repeat length (≤20) polymorphisms are strongly associated with breast carcinomas and atypical hyperplasias. Although non-significant, a subgroup of patients with breast carcinoma and genotype SS showed an association with parameters of worse outcome.

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Introduction: Venous thrombosis (VT) and inflammation are two closely related entities. In the present investigation we assessed whether there is a relation between genetic modifiers of the inflammatory response and the risk of VT. Materials and methods: 420 consecutive and unrelated patients with an objective diagnosis of deep VT and 420 matched controls were investigated. The frequencies of the following gene polymorphisms were determined in all subjects: TNF-α- 308 G/A, LT-α+ 252 A/G, IL-6-174 G/C, IL1-ra 86 bp VNTR, IL-10-1082 A/G and CD-31 125 C/G. Results: Overall odds ratio (OR) for VT related to TNF-α- 308 G/A, LT-α+ 252 A/G, IL-6-174 G/C, A1 allele (4 bp repeat) of the IL1-ra 86 bp VNTR, IL-10-1082 A/G and CD-31 125 C/G were respectively: 1.0 (CI95: 0.8-1.5), 1.3 (CI95: 1.0-1.7), 1.1 (CI95: 0.9-1.5), 1.6 (CI95: 1-2.5), 1.2 (CI95: 0.8-1.7) and 0.8 (CI95: 0.6-1.1). A possible interaction between polymorphisms was observed only for the co-inheritance of the mutant alleles of the LT-α+ 252 A/G and IL-10-1082 G/A polymorphisms (OR = 2; CI95: 1.1-3.8). The risk of VT conferred by factor V Leiden and FII G20210A was not substantially altered by co-inheritance with any of the cytokine gene polymorphisms. Conclusions: Cytokine gene polymorphisms here investigated did not significantly influence venous thrombotic risk. © 2006 Elsevier Ltd. All rights reserved.

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Background: The chemokine receptor 1 CXCR-1 (or IL8R-alpha) is a specific receptor for the interleukin 8 (IL-8), which is chemoattractant for neutrophils and has an important role in the inflammatory response. The polymorphism rs2234671 at position Ex2+860G > C of the CXCR1 gene causes a conservative amino acid substitution (S276T). This single nucleotide polymorphism (SNP) seemed to be functional as it was associated with decreased lung cancer risk. Previous studies of our group found association of haplotypes in the IL8 and in the CXCR2 genes with the multifactorial disease chronic periodontitis. In this study we investigated the polymorphism rs2234671 in 395 Brazilian subjects with and without chronic periodontitis. Findings. Similar distribution of the allelic and genotypic frequencies were observed between the groups (p > 0.05). Conclusions: The polymorphism rs2234671 in the CXCR1 gene was not associated with the susceptibility to chronic periodontitis in the studied Brazilian population. © 2011 Scarel-Caminaga et al; licensee BioMed Central Ltd.

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Background: Chronic inflammation and gastric carcinogenesis show a close association, so gene polymorphisms that modify the intensity of the inflammatory response may contribute to variations in gastric cancer risk. Aims: The purpose of this study was to investigate the combined effect of the pro- and anti-inflammatory cytokines and toll-like receptors polymorphisms on the chronic gastritis and gastric cancer risk in a Brazilian population sample. Methods: We evaluated 669 DNA samples (200 of gastric cancer [GC], 229 of chronic gastritis [CG], and 240 of healthy individuals [C]). Ten polymorphisms were genotyped: IL-1RN and TLR2 -196 to -174 del using the allele-specific PCR method and TNF-A (rs1800629; rs1799724), TNF-B (rs909253), IL-8 (rs4073; rs2227532), IL-10 (rs1800872) and TLR4 (rs4986790; rs4986791) using PCR-RFLP. Results: Polymorphisms TNF-A-308G/A, IL-8-251A/T, TNF-B + 252A/G and TLR4 + 1196C/T were not associated with risk of any gastric lesion. However, an association with increased risk for GC was observed for polymorphisms IL-1RNL/2 (p < 0.001), TNF-A-857C/T (p = 0.022), IL-8-845T/C (p < 0.001), IL-10-592C/A (p < 0.001), TLR2ins/del (p < 0.001), and TLR4 + 896A/G (p = 0.033). In CG, an association was observed only with polymorphisms IL-1RNL/2 and IL-10-592A/C (p < 0.001 for both). A combined analysis of these six polymorphisms associated with GC revealed a profile with two to four combined genotypes which confer a higher risk of gastric carcinogenesis, with an OR increased 2.95-fold to 50.4-fold, highlighting the combinations IL-1RN2/TNF-A-857T/IL-8-845C, IL-1RN2/IL-8-845C/TLR2del, IL-1RN2/IL-10-592A/TLR4 + 896G, IL-10-592A/TLR2del/ TLR4 + 896G, and IL-1RN2/TNFA-857T/IL8-845C/TLR2del. Conclusions: Our findings evidenced that the combined effect of polymorphisms in genes involved in the inflammatory process may potentiate the risk of gastric cancer, thus emphasizing the importance of evaluating multiple polymorphisms together. © 2012 Springer Science+Business Media New York.

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Ghrelin is a gastrointestinal hormone that acts in releasing growth hormone and influences the body general metabolism. It has been proposed as a candidate gene for traits such as growth, carcass quality, and milk production of livestock because it influences feed intake. In this context, the aim of this study was to verify the existence of polymorphisms in the ghrelin gene and their associations with milk, fat and protein yield, and percentage in water buffaloes (Bubalus bubalis). A group of 240 animals was studied. Five primer pairs were used and 11 single nucleotide polymorphisms (SNP) were found in the ghrelin gene by sequencing. The animals were genotyped for 8 SNP by PCR-RFLP. The SNP g.960G>A and g.778C>T were associated with fat yield and the SNP g.905T>C was associated with fat yield and percentage and protein percentage. These SNP are located in intronic regions of DNA and may be in noncoding RNA sites or affect transcriptional efciency. The ghrelin gene in buffaloes influences milk fat and protein synthesis. The polymorphisms observed can be used as molecular markers to assist selection. © 2013 American Dairy Science Association.

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Adiponectin is a hormone involved in energy homeostasis by regulating glucose and lipid metabolism. In addition, the adiponectin gene (ADIPOQ) has polymorphisms that can modulate the circulating concentration of adiponectin. Abnormal adiponectin levels have been associated with pre-eclampsia (PE); however, the influence of genetic polymorphisms on the development of hypertensive disorders of pregnancy is unclear. The aim of this study was to examine whether ADIPOQ polymorphisms are associated with gestational hypertension (GH) and/or PE. We studied 401 pregnant women: 161 healthy pregnant (HP), 113 pregnant with GH and 127 pregnant with PE. ADIPOQ polymorphisms -11391G>A (rs17300539), -11377C>G (rs266729), 45T>G (rs2241766) and 276G>T (rs1501299) were genotyped by allelic discrimination assays using real-time PCR. Haplotypes were inferred using the PHASE 2.1 program. We observed that the genotypic frequencies of the -11377C>G polymorphism were different in PE compared with HP (P<0.0125), with the CT genotype being more commonly found in PE patients than in HP women (P<0.0125). However, allelic frequencies of this single-nucleotide polymorphism were similar between PE and HP (P>0.0125). No difference was observed when GH and HP groups were compared (both P>0.0125). In addition, we found no difference in genotype or allele distributions for the -11391G>A, 45T>G and 276G>T polymorphisms when we compared GH or PE with HP (all P>0.0125). In conclusion, we found a modest association between the CG genotype of the -11377C>G polymorphism and PE.Journal of Human Hypertension advance online publication, 27 June 2013; doi:10.1038/jhh.2013.53.

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The association of genetic polymorphism in the estrogen receptor alpha (ERα) gene and risk for diseases including breast cancer (BC) has been the subject of great interest. Objective: Checking on women with high breast density after menopause, the frequency of the Pvull and Xbal polymorphisms of the ERα gene and the correlation between them and the known risk factors for breast cancer. Method: Observational study with 308 women between 45 and 65 years old with high breast density, without hormonal therapy, menstruation for a year or more, breast and ovarian cancer history. It was characterized in clinical history and physical examination: menarche, menopause, parity, family history of BC, smoking, alcohol intake and body mass index. Results: The allelic and genotypic frequencies for ERα-Pvull and Xbal: p=43.99%; p=56.01%; pp=32.14%; Pp=47.73% and PP=20.13%; X=41.56%; x=58.44%; xx=33.44%; Xx=50.00% and XX=16.56%, respectively. The most frequent risk factors for BC: menarche before 12 years old (35.38%), nulliparity or first child after 28 years old (41.66%), family history of BC (19.16%) and overweight/obesity (62.01%). Conclusion: Allelic and genotypic distribution similar to literature. The risk factors for BC were more prevalent in women with high breast density but without significant associations with these polymorphisms. © 2013 Informa UK Ltd. All rights reserved.

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HIOMT is a gene that encodes hydroxyindole-O-methyltransfe-rase, the final enzyme in the melatonin synthesis pathway. As the timing of melatonin synthesis is different for morning and evening people, it is possible that polymorphisms in genes coding for the enzymes which participate in melatonin synthesis can influence this hormone synthesis and release patterns that may result in different circadian outputs. The aim of this study was to search for polymorphisms in the HIOMT gene and to verify possible associations between genetic variations in this gene and circadian phenotypes in a Brazilian population sample. Among the 44 extreme morning and the 48 extreme evening people, ten polymorphisms were found, being two of them not described so far. Haploview analyses showed linkage disequilibrium between pairs of polymorphisms in the promoter B region. Also, the haplotype AG (rs4446909, rs5989681) is associated with evening preference. The analysis of these data indicates that polymorphisms in the HIOMT gene exhibit a possible trend to influence circadian phenotypes in this Brazilian population sample, possibly affecting the rate and/or level of melatonin synthesis.