Kelly Cristina de Oliveira

Prevalence of the polymorphism MTHFR A1298C and not MTHFR C677T is related to chromosomal aneuploidy in Brazilian Turner Syndrome patients

BACKGROUND Dysfunctions in the folate metabolism can result in DNA hypomethylation and abnormal chromosome segregation. Two common polymorphisms of this enzyme (C677T and A1298C) reduce its activity, but when associated with aneuploidy studies the results are conflicting. The objective of the present study is to analyze the MTHFR gene polymorphisms in women with Turner Syndrome and in a control group, correlating the findings to the chromosomal aneuploidy. METHODS The study comprised 140 patients with Turner Syndrome, of which 36 with chromosome mosaicism and 104 non-mosaics, and a control group of 209 fertile and healthy women without a history of any offspring with aneuploidy. Polymorphisms C677T and A1298C were studied by RFLP-PCR and the results were statistically analyzed. RESULTS The frequency of genotypes MTHFR 677CC, 677CT and 677TT in the patients with Turner Syndrome and chromosome mosaicism was, respectively, 58.3%, 38.9% and 2.8%. Among the patients with non-mosaic Turner Syndrome, 47.1% presented genotype 677CC, 45.2% genotype 677CT, and 7.7% genotype 677TT. Among the 209 individuals of the control group, genotypes 677CC, 677CT and 677TT were found at the following frequencies: 48.3%, 42.1% and 9.6%, respectively. As for polymorphism A1298C, the patients with Turner Syndrome and chromosome mosaicism presented genotypes 1298AA, 1298AC and 1298CC at the following frequencies: 58.3%, 27.8% and 13.9%, respectively. Among the non-mosaic Turner Syndrome patients, genotype 1298AA was found in 36.5%, genotype 1298AC in 39.4%, and genotype 1298CC in 22.1%. In the control group, genotypes 1298AA, 1298AC and 1298CC were present at the following frequencies: 52.6%, 40.7% and 6.7%, respectively. CONCLUSION No correlation was observed between the MTHFR gene polymorphism 677 and chromosomal aneuploidy in the Turner Syndrome patients. However, the MTHFR gene polymorphism at position 1298, mainly genotype 1298CC that reduces the enzyme efficiency, was more frequent in the group of Turner Syndrome patients, suggesting its involvement in mechanisms related to chromosomal imbalances.

Endogenous oestradiol but not testosterone is related to coronary artery disease in men

Objectives  Men die of coronary artery disease (CAD) more often than women. There is evidence that testosterone either is neutral or has a beneficial effect on male cardiovascular disease. The role of oestrogens in male CAD has been less studied. This study was carried out with the purpose of evaluating the relationship between sex hormone levels and CAD.

PTPN22 Polymorphism is Related to Autoimmune Disease Risk in Patients with Turner Syndrome

Individuals with Turner syndrome (TS) clearly have an increased risk for autoimmune diseases. Recently, an allelic variation (C1858T) of the PTPN22 gene was revealed to be associated with the development of autoimmunity. Thus, the aim of this study was to determine the frequency of the PTPN22 C1858T polymorphism in women with Turner syndrome (TS) compared to controls. Case–control study comprises 142 women with TS (cases) and 180 healthy and fertile women without a history of autoimmune disease (controls). Detection of the PTPN22 C1858T polymorphism (rs2476601) was performed by TaqMan real‐time PCR. The chi‐square test was used to compare allele and genotype frequencies between groups and to estimate the Hardy–Weinberg equilibrium. All P‐values were two‐tailed, and 95% confidence intervals (CIs) were calculated. A P‐value <0.05 was considered statistically significant. Genotypes CC, CT and TT of the PTPN22 C1858T polymorphism presented frequencies of, respectively, 67.6%, 28.2% and 4.2% in the TS, and 82.8%, 16.1% and 1.1% in the control group (P = 0.0043). Alleles C and T were present in, respectively, 81.7% and 18.3% of the patients with TS (P = 0.001, OR = 2.22, 95% CI = 1.39‐3.54) and in 90.8% and 9.2%, respectively, of the controls. The data suggest that in Brazilian patients with TS, the PTPN22 C1858T polymorphism may be an important genetic factor predisposing to autoimmune disease risk.

C677T and A1298C Polymorphisms of MTHFR Gene and Their Relation to Homocysteine Levels in Turner Syndrome

AIMS To determine the frequency of C677T and A1298C polymorphisms of the MTHFR gene and correlate them with homocysteine serum levels in patients with Turner syndrome (TS) and controls. METHODS This case-control study included 78 women with TS and a control group of 372 healthy individuals without personal or family history of cardiovascular disease and cancer. C677T (rs1801133) and A1298C (rs1801131) polymorphisms were detected by polymerase chain reaction-restriction fragment-length polymorphism and the TaqMan system, respectively. Homocysteine serum levels were determined by high-performance liquid chromatography. The results were analyzed statistically, and p<0.05 was considered to represent a significant difference. RESULTS The homocysteine levels change was 13.9+3.3 nM in patients with TS and 8.8+3.2 nM in the control group. No significant difference between groups was found (p=0.348). Single-marker analysis revealed no association between MTHFR C677T polymorphism and TS when genotype (p=0.063) or allelic (p=0.277) distribution was considered. Regarding MTHFR A1298C polymorphism, a statistical difference was found between the TS group and the control group, for both genotype (p<0.0001) and allele (p<0.0001) distribution. Haplotype analysis of 2 MTHFR polymorphisms identified 2 haplotypes-CC and TC-associated with TS (p<0.001 and p=0.0165, respectively). However, homocysteine levels were not higher in patients with haplotype risk. CONCLUSION The results suggest that the C677T and A1298C polymorphisms of the MTHFR gene are not related to homocysteine levels in Brazilian patients with TS, despite the differential distribution of the mutated allele C (A1298C) in these patients. Further studies are needed to investigate the possible genetic interaction with homocysteine levels in TS.

Analysis of vitamin D receptor gene (VDR) polymorphisms in Turner syndrome patients

Individuals with Turner syndrome (TS) have increased risk for autoimmune diseases, especially thyroid abnormalities. The function of the vitamin D receptor (VDR) gene is influenced by several genetic polymorphisms which are associated with a susceptibility to a range of autoimmune diseases. Thus, we have hypothesized a possible relationship between thyroid abnormalities and VDR polymorphisms (ApaI/G1025-49T, TaqI/T1056C, FokI/T2C and BsmI G1024 + 283A) in TS patients. A case-control study was performed comprising 101 Brazilian women with TS and a control group consisting of 133 healthy fertile women without a history of autoimmune diseases. In TS group, 21.8% had Hashimoto’s thyroiditis. Detection of VDR polymorphisms was performed using TaqMan system by real-time PCR. The χ2 was used to compare allele and genotype frequencies between groups. Combined genotypes of VDR gene polymorphisms were assessed by the haplotype analysis. A p value <0.05 was considered statistically significant. Relatively similar VDR polymorphisms genotype and allelic frequencies in cases and controls were found, even when only considering the patients with thyroid abnormalities. Haplotype analysis showed that none of the VDR haplotypes were associated to thyroid diseases in TS patients. In conclusion, the results showed no association between VDR gene polymorphisms and thyroid abnormalities in Brazilian TS patients tested.

[From Decourt sex chromatin to real time PCR: cytogenetic and gene expression in the Turner syndrome study].

Em 1930, o pediatra alemao Otto Ullrich relatou o caso de uma menina de 8 anos de idade que apresentava palato em ogiva, ptose palpebral, orelhas de implantacao baixa, linfedema, baixa estatura, ausencia de desenvolvimento de mamas, ausencia ou quantidade minima de pelos pubianos e axilares, cubito valgo e pescoco alado. No entanto, a primeira visao equivalente a sindrome foi feita por Morgagni em 1761 (1). Em 1938, Henry Turner (2) publicou a descricao de pacientes do sexo feminino que se caracterizavam por apresentar os mesmos sinais descritos por Otto Ullrich (1930). Quatro anos depois, Varney e cols. (3) e Albright e Smith (4), independentemente, demonstraram em pacientes com sinais clinicos semelhantes aos daqueles descritos por Turner que, apos a idade puberal, apresentavam um elevado nivel de gonadotrofinas urinarias, estabelecendo que se tratava de uma anormalidade da funcao gonadal e nao uma deficiencia hipotalâmica ou hipofisaria. Em 1944, Wilkins e Fleischmann (5) observaram, em analises histologicas, que as pacientes com os sinais descritos por Turner (2), Varney e cols. (3) e Albright e Smith (4) deveriam ter gonadas em fita e que todos esses autores estavam estudando a mesma sindrome: a sindrome de Turner (ST). A primeira investigacao cromossomica dessa sindrome foi realizada na Escola Paulista de Medicina, hoje Universidade Federal de Sao Paulo − Unifesp, em 1954 por Decourt e cols. (6) que demonstraram que os sinais fenotipicos caracteristicos da ST eram decorrentes da ausencia da cromatina sexual. Em 1959, Ford e cols. (7) descreveram a anormalidade cromossomica que caracterizava a sindrome de Turner: monossomia do cromossomo sexual X, o cariotipo 45,X. Dados de literatura referem que um segundo cromossomo sexual e necessario a sobrevivencia do feto e, desse modo, virtualmente todo nascido vivo 45,X apresentaria mais de uma linhagem celular compondo seu cariotipo, constituindo assim um mosaico. Essa condicao seria necessaria a pelo menos alguns orgaos, durante determinado periodo da embriogenese. Essa hipotese se baseia em dois pontos principais: a frequencia de mosaicismo do cromossomo sexual e muito superior em nascidos vivos com ST em relacao a observada em abortos; estima-se que aproximadamente 99% dos embrioes puramente 45,X morrem no utero. Todavia, a selecao natural nem sempre prevalece quando o mosaicismo esta presente, apesar de o resultado fenotipico ser semelhante (8). A deteccao de mosaicismo e determinada, principalmente, por quatro fatores: o tipo e o numero de tecidos analisados, o numero de celulas estudadas, a sensibi1 Disciplina de Endocrinologia, Departamento de Medicina, Universidade Federal de Sao Paulo (Unifesp), Sao Paulo, SP, Brasil

Emprego da cromatografia líquida de alta eficiência na determinação de cortisol sérico em substituição à técnica de radioimunoensaio

BACKGROUND: The quantification of cortisol in different organic fluids has not only been applied to different human nosological conditions as a diagnostic aid but it has also been used in clinical research. In clinical application, cortisol is routinely measured by radioimmunoassay (RIA). In the determination of free urinary cortisol this technique has been replaced by the high-performance liquid chromatography mainly in the diagnosis of Cushing syndrome. As to serum cortisol determination, there is no evidence of the application of liquid chromatography as a substitute for other analytical techniques. OBJECTIVE: The development of an analytical methodology using reversed-phase high-performance liquid chromatography (RP-HPLC) to determine serum cortisol levels as a substitute for RIA in order to reduce radioactive waste. MATERIAL AND METHODS: Cortisol was directly quantified by RP-HPLC in previously ether-extracted serum samples. Triamcinolone acetonide was used as internal standard (IS). The chromatographic separation was developed in a BDS-Hypersil-C18® column (125 x 4 mm, 5 µm) using water-acetonitrile (72:28; v/v) as mobile phase at 1 ml/min and steroid peaks were measured at 243 nm. RESULTS: Cortisol and IS presented retention time of 3.4 and 7.1 min, respectively. The precision was less than 10% and accuracy was less than 4%. DISCUSSION: The method was effective and efficient, with good sensitivity and linearity in the concentration range of 2.5 to 60.0 µµg/dl. CONCLUSION: The present methodology substitutes RIA at clinical application.