Effect of MTHFR A1298C and MTRR A66G Genetic Mutations on Homocysteine Levels in the Chinese Population: A Systematic Review and Meta-analysis

Effects of methionine synthase and methionine synthase reductase polymorphisms on hypertension susceptibility

BACKGROUND

Polymorphisms of methylenetetrahydrofolate reductase (MTHFR) gene are strongly associated with hypertension incidence, although such association is inconsistent among ethnicities studied. However, effects of polymorphisms of other genes related to folate metabolism besides MTHFR on hypertension susceptibility are not well known yet.

OBJECTIVE

The aim of this study was to elucidate whether methionine synthase (MTR) 2756A>G and methionine synthase reductase (MTRR) 66A>G polymorphisms might be associated with risks of hypertension susceptibility in the Korean population.

METHODS

Genotyping of these two polymorphisms was performed for 232 hypertensive patients and 247 unrelated healthy controls using polymerase chain reaction-restriction fragment length polymorphism technique.

RESULTS

In the present study, mutations of MTR 2756A>G and MTRR 66A>G polymorphisms were associated with increased and decreased susceptibility to hypertension, respectively. Allele combinations from these two polymorphisms were also related to hypertension prevalence. When polymorphism data were stratified according to clinical components of hypertension, The G allele of MTR 2756A>G polymorphism was significantly associated with an increased risk of hypertension in subjects with BMI < 26.1 kg/m² (P = 0.004), WC < 87.2 in. (P = 0.021), FBG < 95.5 mg/dL (P = 0.011), triglyceride < 133.5 mg/dL (P = 0.034), and HDL-cholesterol < 52.2 mg/dL (P = 0.036). The G allele of MTRR 66A>G polymorphism was significantly associated with a decreased risk of hypertension in subjects with WC ≥ 87.2 in. (P = 0.029), FBG ≥ 95.5 mg/dL (P = 0.032) and triglyceride ≥ 133.5 mg/dL (P = 0.027).

CONCLUSION

MTR 2756A>G and MTRR 66A>G polymorphisms related to folate metabolism might be genetic markers for risk of hypertension in the Korean population.

Evaluation of right ventricular volume and systolic function in normal fetuses using intelligent spatiotemporal image correlation

BACKGROUND

Heart defects are the most common congenital malformations in fetuses. Fetal cardiac structure and function abnormalities lead to changes in ventricular volume. As ventricular volume is an important index for evaluating fetal cardiovascular development, an effective and reliable method for measuring fetal ventricular volume and cardiac function is necessary for accurate ultrasonic diagnosis and effective clinical treatment. The new intelligent spatiotemporal image correlation (iSTIC) technology acquires high-resolution volumetric images. In this study, the iSTIC technique was used to measure right ventricular volume and to evaluate right ventricular systolic function to provide a more accurate and convenient evaluation of fetal heart function.

AIM

To investigate the value of iSTIC in evaluating right ventricular volume and systolic function in normal fetuses.

METHODS

Between October 2014 and September 2015, a total of 123 pregnant women received prenatal ultrasound examinations in our hospital. iSTIC technology was used to acquire the entire fetal cardiac volume with off-line analysis using QLAB software. Cardiac systolic and diastolic phases were defined by opening of the atrioventricular valve and the subsequent closure of the atrioventricular valve. The volumetric data of the two phases were measured by manual tracking and summation of multiple slices and recording of the right ventricular end-systolic volume and the right ventricular end-diastolic volume. The data were used to calculate the right stroke volume, the right cardiac output, and the right ejection fraction. The correlations of changes between the above-mentioned indices and gestational age were analyzed. The right ventricular volumes of 30 randomly selected cases were measured twice by the same sonographer, and the intra-observer agreement measurements were calculated.

RESULTS

Among the 123 normal fetuses, the mean right ventricular end-diastolic volume increased from 0.99 ± 0.34 mL at 22 wk gestation to 3.69 ± 0.36 mL at 35⁺⁶ wk gestation. The mean right ventricular end-systolic volume increased from 0.43 ± 0.18 mL at 22 wk gestation to 1.36 ± 0.22 mL at 35⁺⁶ wk gestation. The mean right stroke volume increased from 0.62 ± 0.29 mL at 22 wk gestation to 2.33 ± 0.18 mL at 35⁺⁶ wk gestation. The mean right cardiac output increased from 92.23 ± 40.67 mL/min at 22 wk gestation to 335.83 ± 32.75 mL/min at 35⁺⁶ wk gestation. Right ventricular end-diastolic volume, right ventricular end-systolic volume, right stroke volume, and right cardiac output all increased with gestational age and the correlations were linear (P < 0.01). Right ejection fraction had no apparent correlation with gestational age (P > 0.05).

CONCLUSION

Fetal right ventricular volume can be quantitatively measured using iSTIC technology with relative ease and high repeatability. iSTIC technology is expected to provide a new method for clinical evaluation of fetal cardiac function.

Associations of MTRR and TSER polymorphisms related to folate metabolism with susceptibility to metabolic syndrome

BACKGROUND

Hyperhomocysteinemia is a potential risk factor for the development of metabolic syndrome (MetS). Among genes involved in homocysteine metabolism, polymorphisms of methylenetetrahydrofolate reductase (MTHFR) gene are known to be associated with MetS incidence. However, effects of polymorphisms of other folate metabolism-related genes on MetS susceptibility are not well known yet.

OBJECTIVE

This study was to determine whether methionine synthase (MTR) 2756A > G, methionine synthase reductase (MTRR) 66A > G, and thymidylate synthase enhancer region (TSER) 2R/3R polymorphisms might be associated with risks of MetS development in the Korean population.

METHODS

Genotype analysis of the three polymorphisms was performed for a total of 483 subjects including 236 MetS patients and 247 unrelated healthy controls using polymerase chain reaction-restriction fragment length polymorphism technique.

RESULTS

The present study revealed that MTRR and TSER polymorphisms were associated with susceptibility to MetS. Several genotypes and allele combinations from the three polymorphisms were also related to the MetS prevalence. When polymorphism data were stratified according to the risk components of MetS, MTR polymorphism was significantly associated with an increased risk of MetS in subjects with systolic blood pressure < 132.7 mmHg (AOR 1.842, 95% CI 1.039-3.266, P = 0.037) and fasting blood glucose level < 106.3 mg/dL (AOR 1.772, 95% CI 1.069-2.937, P = 0.027). MTRR polymorphism was significantly associated with a decreased risk of MetS in subjects with triglyceride level < 216.3 mg/dL (AOR 0.616, 95% CI 0.399-0.951, P = 0.029). To the best of our knowledge, this is the first to provide reliable evidence about the association of other folate metabolism-related gene polymorphisms besides MTHFR with MetS susceptibility and its risk factors.

CONCLUSION

Results of this study suggest that MTRR and TSER polymorphisms might be potential genetic markers for the risk of MetS development in Korean population.

Clinical Implications of Methotrexate Pharmacogenetics in Childhood Acute Lymphoblastic Leukaemia

Background:

In the past two decades, a great body of research has been published regarding the effects of genetic polymorphisms on methotrexate (MTX)-induced toxicity and efficacy. Of particular interest is the role of this compound in childhood acute lymphoblastic leukaemia (ALL), where it is a pivotal drug in the different treatment protocols, both at low and high doses. MTX acts on a variety of target enzymes in the folates cycle, as well as being transported out and into of the cell by several transmembrane proteins.

Methods:

We undertook a structured search of bibliographic databases for peer-reviewed research literature using a focused review question.

Results:

This review has intended to summarize the current knowledge concerning the clinical impact of polymorphisms in enzymes and transporters involved in MTX disposition and mechanism of action on paediatric patients with ALL.

Conclusion:

In this work, we describe why, in spite of the significant research efforts, pharmacogenetics findings in this setting have not yet found their way into routine clinical practice.