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 χ(2) 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.

A specific bioelectrical impedance equation to predict body composition in Turner's syndrome.

INTRODUCTION: Cardiovascular disease is one of the main causes for Turner syndrome (TS) mortality and the evaluation of its risk factors such as excess body fat and its distribution is considered one of the major aspects of the adult patient care. OBJECTIVE: To develop and validate a specific bioelectrical impedance analysis (BIA) equation to predict body composition in TS patients. SUBJECTS AND METHODS: Clinical and anthropometric data, dual-energy X-ray absorptiometry (DXA) for total fat-free mass (FFM) and BIA for resistance and reactance were obtained from 50 adult TS patients. Linear regression analysis was performed with multiple clinical and BIA data to obtain a predicting equation. RESULTS: The equation developed to estimate FFM in adult TS patients showed great consistency with DXA, elevated correlation (r = 0.974) and determination (r(2) = 0.948) coefficients and an adequate standard error estimate (SEE = 1.52 kg). CONCLUSIONS: The specific equation developed here allowed making an adequate FFM estimate in adult TS patients.

OCT4 gonadal gene expression related to the presence of Y-chromosome sequences in Turner syndrome.

To show that in the dysgenetic gonads of 104 Turner syndrome patients no significant difference was found regarding the expression of the genes DAX1, FOG2, GATA4, OCT4, SF1, SRY, TSPY, WT1, and STRA8 compared with controls, except for genes OCT4, SRY, and TSPY in both gonads of a patient whose chromosomal constitution was 45,X/45,X,add(15)(p11). The expression analysis of genes OCT4, SRY, and TSPY in the dysgenetic gonads of Turner syndrome patients may allow introducing modifications in the microenvironment that could contributed to a malignant transformation process.

A specific bioelectrical impedance equation to predict body composition in Turner's syndrome / Uma equação de bioimpedanciometria específica para predição de composição corporal na síndrome de Turner

INTRODUCTION: Cardiovascular disease is one of the main causes for Turner syndrome (TS) mortality and the evaluation of its risk factors such as excess body fat and its distribution is considered one of the major aspects of the adult patient care. OBJECTIVE: To develop and validate a specific bioelectrical impedance analysis (BIA) equation to predict body composition in TS patients. SUBJECTS AND METHODS: Clinical and anthropometric data, dual-energy X-ray absorptiometry (DXA) for total fat-free mass (FFM) and BIA for resistance and reactance were obtained from 50 adult TS patients. Linear regression analysis was performed with multiple clinical and BIA data to obtain a predicting equation. RESULTS: The equation developed to estimate FFM in adult TS patients showed great consistency with DXA, elevated correlation (r = 0. 974) and determination (r² = 0. 948) coefficients and an adequate standard error estimate (SEE = 1.52 kg). CONCLUSIONS: The specific equation developed here allowed making an adequate FFM estimate in adult TS patients.

INTRODUÇÃO: A doença cardiovascular é uma das principais causas de mortalidade na síndrome de Turner (ST) e a avaliação de seus fatores de risco, como excesso e distribuição de gordura corporal, é considerada uma das principais metas da assistência às pacientes adultas. OBJETIVO: Desenvolver e validar uma equação de análise por bioimpedanciometria específica para estimar massa magra na ST. SUJEITOS E MÉTODOS: Foram obtidos dados clínicos, antropométricos, densitometria para massa magra total e bioimpedanciometria para resistência e reactância de 50 mulheres adultas com ST. Para obter uma equação preditora, foi realizada análise de regressão linear com múltiplos dados clínicos e da bioimpedanciometria. RESULTADOS: A equação desenvolvida para estimar massa magra na ST demonstrou grande concordância com a densitometria, elevados coeficientes de correlação (r = 0,974) e determinação (r² = 0,948) e um adequado erro padrão da estimativa (SEE = 1,52 kg). CONCLUSÕES: A equação desenvolvida possibilitou uma adequada estimativa da massa magra em adultas com ST.

Evaluation of clinical checklists for fragile X syndrome screening in Brazilian intellectually disabled males: proposal for a new screening tool.

Patients with fragile X syndrome present a variable phenotype, which contributes to the underdiagnosing of this condition. The use of clinical checklists in individuals with intellectual disability can help in selecting patients to be given priority in the molecular investigation of the fragile X mutation in the FMR1 gene. Some features included in checklists are better predictors than others, but they can vary among different populations and with patient age. In the present study, we evaluated 20 features listed in four clinical checklists from the literature, using a sample of 192 Brazilian male patients presenting with intellectual disability (30 positive and 162 negative for fragile X mutation). After statistical analysis, 12 out of the 20 items analyzed showed significant differences in their distributions between the two groups. These features were grouped in a new checklist that can help clinicians in their referral for fragile X testing in patients with developmental delay.

[Growth hormone treatment inTurner syndrome: data and reflections]. / O hormônio de crescimento na síndrome de Turner: dados e reflexões.

Short stature is the major characteristic of Turner syndrome. The statural appeal is premature and become evident in the puberty. Haploinsufficiency of SHOX gene has been related as main factor on final height of these patients. Despite the majority of the patients are not growth hormone deficient, the GHr therapy improves the final height. Recently, a great number of publications have described the association between GH and cancer. The cancer risk, in these patients, is mainly associated with the presence of Y chromosome sequences that can lead to the gonadoblastoma development. In conclusion, the GHr therapy in ST patients deserves caution. The investigation of Y chromosome sequences should be performed as well as the prophylactic gonadectomy in the positive cases conferring confidence to the treatment.

O hormônio de crescimento na síndrome de Turner: dados e reflexões: [revisão] / Growth hormone treatment inTurner syndrome: data and reflections: [review]

A baixa estatura é a principal característica na síndrome de Turner (ST). O agravo estatural na ST é precoce e torna-se mais evidente na puberdade. A haploinsuficiência do gene SHOX tem sido implicada como principal fator na definição da estatura de mulheres, no entanto, ainda que a maioria das pacientes não tenha deficiência do hormônio de crescimento, a terapia com GHr melhora a altura final. Recentemente, tem-se chamado a atenção para a associação entre GH e câncer. O risco de câncer nessas pacientes está associado à presença de fragmentos do cromossomo Y que pode levar ao desenvolvimento de gonadoblastoma. Dessa forma, a administração de GHr na ST deve ser feita com cautela. A investigação de seqüências do cromossomo Y deve ser realizada, bem como a gonadectomia profilática nos casos positivos, conferindo maior segurança ao tratamento.

Short stature is the major characteristic of Turner syndrome. The statural appeal is premature and become evident in the puberty. Haploinsuficiency of SHOX gene has been related as main factor on final height of these patients. Despite the majority of the patients are not growth hormone deficient, the GHr therapy improves the final height. Recently, a great number of publications have described the association between GH and cancer. The cancer risk, in these patients, is mainly associated with the presence of Y chromosome sequences that can lead to the gonadoblastoma development. In conclusion, the GHr therapy in ST patients deserves caution. The investigation of Y chromosome sequences should be performed as well as the prophylactic gonadectomy in the positive cases conferring confidence to the treatment.

Clinical checklists in the selection of mentally retarded males for molecular screening of fragile X syndrome

Fragile X syndrome is the most frequent cause of inherited mental retardation. The phenotype in this syndrome is quite variable and less conspicuous in younger patients, making clinical diagnosis difficult and thus making molecular diagnosis necessary. The use of clinical checklists in mentally retarded individuals can help selecting patients to be given priority in the molecular investigation for the fragile-X mutation in the FMR1 gene. We evaluated two clinical checklists in a sample of 200 Brazilian male patients with mental retardation. The highest scores in the two checklists concentrated among the 19 males (9.5 percent) found to carry full mutations. Our results confirm the importance of fragile-X checklists as a clinical tool in the study of mentally retarded patients.

Determination of the sexual phenotype in a child with 45,X/46,X,Idic(Yp) mosaicism: importance of the relative proportion of the 45,X line in gonadal tissue.

We report on a girl who, despite her 45,X/46,X,der(Y) karyotype, showed no signs of virilization or physical signs of the Ullrich-Turner syndrome (UTS), except for a reduced growth rate. After prophylactic gonadectomy due to the risk of developing gonadoblastoma, the gonads and peripheral blood samples were analyzed by fluorescence in situ hybridization (FISH) and polymerase chain reaction (PCR) to detect Y-specific sequences. These analyses allowed us to characterize the Y-derived chromosome as being an isodicentric Yp chromosome (idic(Yp)) and showed a pronounced difference in the distribution of the 45,X/46,X,idic(Yp) mosaicism between the two analyzed tissues. It was shown that, although in peripheral blood almost all cells (97.5%) belonged to the idic(Yp) line with a duplicated SRY gene, this did not determine any degree of male sexual differentiation in the patient, as in the gonads the predominant cell line was 45,X (60%).