Iwona Gorący

C677T polymorphism of the methylenetetrahydrofolate reductase gene and the risk of ischemic stroke in Polish subjects

Hyperhomocysteinemia is reported to be an independent risk factor for the development of ischemic stroke. Several studies on genetic variants of methylenetetrahydrofolate reductase (MTHFR, which plays a crucial role in regulation of plasma homocysteine concentration) reported an association between C677T gene polymorphism and stroke in some Asian populations. No study but one detected this association in Caucasians. The purpose of the present case-control study was to find a relationship betweenMTHFR genotypes and stroke in a Polish population.MTHFR genotypes were determined by PCR in 152 patients with ischemic stroke from northwestern Poland and in 135 consecutive newborns from the same population. The TT genotype and the T allele were significantly more frequent in patients than in the control group (11.8% vs. 4.4%, and 34.5% vs. 21.5%,P < 0.01). When males and females were analyzed separately, the differences were statistically significant in both genders. It is concluded that presence of the T allele is a risk factor for ischemic stroke in Polish subjects.

Association of Glucocorticoid Receptor Gene NR3C1 Genetic Variants with Angiographically Documented Coronary Artery Disease and Its Risk Factors

BACKGROUND AND AIMS Glucocorticoids and their receptors are involved in inflammation and many cardiovascular risk factors. We examined associations of Tth111I, N363S and ER22/23EK NR3C1 gene polymorphisms and haplotypes, with coronary artery disease (CAD), severity of CAD (single-vessel vs. multivessel disease) and risk factors. METHODS Three hundred ten individuals were submitted to coronary angiography. Selected genotypes were determined by PCR-RFLP. RESULTS Carriers of the Tth111I allele T were found significantly less often in the CAD compared with the non-CAD group (49.7 vs. 64.6%, p = 0.013); this association was similar for TGA haplotype carriers (49.2 vs. 62.8%, p = 0.024); the T allele was more frequent in females (66.3 vs. 51.1%, p = 0.020) and its presence was associated with higher levels of HDL-cholesterol (46.6 ± 12.7 vs. 43.5 ± 10.1 mg/dL for T-carriers vs. noncarriers, p = 0.045). The TT genotype proved to be less common in MVD than SVD (5.9 vs. 14.1%, p = 0.075). The 363S allele was significantly associated with diabetes mellitus (DM) (24.4 vs. 10.9%; carriers in DM and non-DM subjects, respectively, p = 0.027), the TT genotype or TGA/TGA diplotype (in which the 363S allele was absent) were less frequent in DM than in non-DM subjects (p = 0.012 for Tth111I-TT and p = 0.020 for TGA/TGA diplotype). No significant associations between CAD and N363S or ER22/23EK polymorphisms were found. CONCLUSIONS Our results suggest that the Tth111I NR3C1 polymorphism may play a protective role in the development of CAD, and homozygous TT in development of MVD. The N363S polymorphisms may contribute to the development of diabetes in the Polish population.

Common Genetic Variants of the BMP4, BMPR1A, BMPR1B, and ACVR1 Genes, Left Ventricular Mass, and Other Parameters of the Heart in Newborns

The members of the family of bone morphogenetic proteins (BMPs) are important regulators in cardiac development. The present study was designed to evaluate the effect of common genetic variants of BMP-4 and its receptors BMPR1A, BMPR1B, and ACVR1 on left ventricular mass (LVM) and other parameters of the heart and blood pressure in newborns. The study included 210 healthy newborns. Two-dimensional M-mode echocardiography was used to assess LVM between days 3 and 4 after birth. Polymorphisms were determined by the polymerase chain reaction-restriction fragment length polymorphism technique. We found lack of associations between LVM, values of blood pressure, and the BMP4, BMPR1A, BMPR1B, and ACVR1 genotypes. A significant association was observed between the 455C allele of BMP4 and increased left ventricular internal diameter systolic (p=0.004) and between 1650T allele of BMPR1B and lower left atrium diameter (p=0.038). Presence of the 455C allele of BMP4 and the 8474T allele of ACVR1 gene was significantly associated with decreased left ventricular ejection fraction (LVEF) (p=0.0004 and p=0.046, respectively). The 455C allele of BMP4 and the 8474T allele of ACVR1 may play a role as significant predictors for decreased LVEF in newborns.

Genetics of the renin-angiotensin system with respect to cardiac and blood pressure phenotypes in healthy newborn infants.

Introduction: Left ventricular mass (LVM) is a strong predictor of various heart diseases. We examine the association between the G(-6)A AGT, I/D ACE, A1166C AGTR1, T(-344)C CYP 11β2, A538G MR and A10631G REN polymorphisms and LVM and blood pressure in newborn infants. Material and methods: The study included 211 healthy newborn infants. Two-dimensional M-mode echocardiography was used to assess LVM between days 3–4 after birth. Polymorphisms were determined by polymerase chain reaction - restriction fragment length polymorphism (PCR-RLFP). Results: AGTR1 genotype was significantly associated with neonatal systolic blood pressure (≥90 percentile). LVM indexes (LVMIs) were tested for association with genotypes in multivariate analysis. The carriers of the A allele of the AGT polymorphism had significantly higher LVM/body length (BL) values when compared with newborn infants homozygous for the G allele (padjusted=0.03). The higher LVM/BL values were seen in the carriers of the A alleles of the AGTR1 polymorphism (padjusted=0.046). All examined indexes (LVM/body surface area (BSA), LVM/BL, LVM/bodyweight (BW)) were associated with CYP11B polymorphism. The newborn infants homozygous for the T allele had significantly higher values of LVM/BSA, LVM/BL, and LVB/BW compared to non-TT-homozygous neonates (padjusted=0.003; padjusted=0.003; padjusted=0.004 respectively). Conclusion: The AGT, AGTR1, CYP11β polymorphisms are associated with increased LVMIs in newborns. This observation indicates that genetic factors may be modulating LVM at birth.

Epistatic interaction between common AGT G(-6)A (rs5051) and AGTR1 A1166C (rs5186) variants contributes to variation in kidney size at birth.

Low nephron number has been recognised as an important cardiovascular risk factor and recently a strong correlation between renal mass and nephron number has been demonstrated in newborns. The aim of this study was to investigate individual, as well as combined, effects of common variants of genes which encode for major components of the renin-angiotensin system (REN G10601A, AGT G(-6)A, ACE I/D, AGTR1 A1166C) on kidney size in healthy, full-term newborns. A significant additive main effect of the ACE I/D polymorphism, as well as an additive-by-additive interaction between AGT G(-6)A and AGTR1 A1166C variants, were found. The variance attributed to the epistatic effect was 27.9 ml(2)/m(4), which accounted for 73.8% of the interaction variance (37.8 ml(2)/m(4)), 66.4% of the genetic variance (42.0 ml(2)/m(4)) and 4.4% to the total phenotypic variance (628 ml(2)/m(4)). No other statistically significant main or epistatic effects were detected. Our results highlight the importance of considering gene-gene interactions as part of the genetic architecture of congenital nephron number, even when the loci do not show significant single locus effects. Unravelling the genetic determinants of low nephron number, along with early molecular screening, may well help to identify children at risk for cardiovascular disease.

Association of functional genetic variants of A-kinase anchoring protein 10 with QT interval length in full-term Polish newborns.

Introduction A-Kinase Anchoring Proteins (AKAPs) coordinate the specificity of protein kinase A signaling by localizing the kinase to subcellular sites. The 1936G (V646) AKAP10 allele has been associated in adults with low cholinergic/vagus nerve sensitivity, shortened PR intervals in ECG recording and in newborns with increased blood pressure and higher cholesterol cord blood concentration. The aim of the study was to answer the question of whether 1936A > G AKAP10 polymorphism is associated with the newborn electrocardiographic variables. Material and methods Electrocardiograms were recorded from 114 consecutive healthy Polish newborns (55 females, 59 males), born after 37 gestational weeks to healthy women with uncomplicated pregnancies. All recordings were made between 3rd and 7th day of life to avoid QT variability. The heart rate per minute and duration of PR, QRS, RR and QT intervals were usually measured. The ECGs were evaluated independently by three observers. At birth, cord blood of neonates was obtained for isolation of genomic DNA. Results The distribution of anthropometric and electrocardiographic variables in our cohort approached normality (skewness < 2 for all variables). No significant differences in anthropometric variables and electrocardiographic traits with respect to AKAP10 genotype were found. Multiple regression analysis with adjustment for gender, gestational age and birth mass revealed that QTc interval in GG AKAP10 homozygotes was significantly longer, but in range, when compared with A alleles carriers (AA + AG, recessive mode of inheritance). No rhythm disturbances were observed. Conclusions Results demonstrate possible association between AKAP10 1936A > G variant and QTc interval in Polish newborns.

An insertion/deletion ACE polymorphism and kidney size in Polish full-term newborns

The number of nephrons is a multifactorial trait controlled by the interaction of environmental factors and genetic variants that influence the extent of branching nephrogenesis during foetal life. A correlation between renal mass and nephron number in newborns allows the use of the total kidney volume at birth as a surrogate for congenital nephron number. Since the renin–angiotensin system plays an important role in renal development we hypothesized that the common, functional insertion/deletion (I/D) polymorphism in the ACE gene might be responsible for the variation in kidney size amongst healthy individuals. We recruited 210 healthy Polish full-term newborns born to healthy women with uncomplicated pregnancies. The kidney volume was measured sonographically. Total kidney volume (TKV) was calculated as the sum of left kidney volume and right kidney volume. TKV was normalized to body surface area (TKV/BSA). The I and D alleles were identified using polymerase chain reaction. TKV/BSA in newborns carrying at least one insertion ACE allele was significantly reduced by approximately 8% as compared with homozygous newborns for the D allele (DD genotype) (105.1±23.6 vs. 114.2±28.2 cm3/m2, p<0.05). The results of this study suggest that I/D ACE polymorphism may account for subtle variation in kidney size at birth, which reflects congenital nephron endowment.

VAMP-8 gene variant is associated with increased risk of early myocardial infarction.

Introduction Single nucleotide polymorphism in the 3’ untranslated region of the vesicle-associated membrane protein gene (VAMP-8) has been associated with increased risk of early-onset myocardial infarction (MI). In this study the risk of early onset MI conferred by VAMP-8 gene polymorphism was investigated in a group of 171 male subjects. Material and methods Male patients with a history of MI who underwent coronary angiography were enrolled and divided into early (incident < 55 years of age) and late (incident ≥ 55 years of age) MI onset groups. Apart from the RFLP-PCR based analysis of the VAMP-8 variant, history of hypertension, lipid abnormalities, smoking and body mass index were recorded. In statistical analyses odds ratios and relative risk were used as a measure of genotype-MI association while logistic regression was implemented for evaluation of MI risk factor strength. Results VAMP-8 A allele frequency proved to be significantly higher in the early-onset MI group and conferred higher relative risk of early MI in the investigated cohort, when calculated for the individual A allele (p = 0.029). In logistic regression analyses no association between risk genotypes and traditional risk factors was observed. Conclusions In this study VAMP-8 A variant was identified as a risk allele for early MI in male subjects.

Association of Genetic Variation in Calmodulin and Left Ventricular Mass in Full-Term Newborns

Calmodulin II (CALM2) gene polymorphism might be responsible for the variation in the left ventricular mass amongst healthy individuals. The aim was to evaluate the correlation between left ventricular mass (LVM) and g.474955027G>A (rs7565161) polymorphism adjacent to the CALM2 gene. Healthy Polish newborns (n = 206) were recruited. Two-dimensional M-mode echocardiography was used to assess LVM. Polymorphisms were determined by polymerase chain reaction-restriction fragment length polymorphism and sequencing analyses. The carriers of the G allele of the CALM2 polymorphism had significantly higher left ventricular mass/weight (LVM/BW) values, when compared with newborns homozygous for the A allele (3.1 g/m2 versus 2.5 g/m2, P adjusted = 0.036). The AG genotype of CALM2 was associated with the highest values of LVM/BW, exhibiting a pattern of overdominance (2.9 g/kg versus 3.1 g/kg versus 2.5 g/kg, P adjusted = 0.037). The results of this study suggest that G>A CALM2 polymorphism may account for subtle variation in LVM at birth.