Association of Intelectin 1 Gene rs2274907 A > T Polymorphism with Obesity, Type 2 Diabetes, Serum Intelectin-1 Levels and Lipid Profiles in Turkish Adults

The anti-inflammatory adipokine intelectin-1, which is encoded by the ITLN1 gene, is hypothesized to be linked to the pathogenesis of type 2 diabetes (T2DM) and obesity. The purpose of this study was to examine the effect of the ITLN1 gene polymorphism rs2274907 on obesity and T2DM in Turkish adults. The impact of genotype on lipid profiles and serum intelectin levels in the obese and diabetes groups was also investigated. Randomly selected 2266 adults (mean age, 55.0 ± 11.7 years; 51.2% women) participating in the population-based Turkish adult risk factor study were cross-sectionally analyzed. The genotyping of rs2274907 A > T polymorphism was performed by using the hybridization probe based LightSNiP assay in real-time PCR. T2DM were defined using the criteria of the American Diabetes Association. Obesity was described as Body mass index ≥ 30 kg/m2. Statistical analyses were used to investigate the association of genotypes with clinical and biochemical measurements. According to findings, there was no vital connection between the rs2274907 polymorphism and obesity, T2DM, or serum intelectin-1 level. The TA+AA carriers had significantly higher triglyceride levels (p = 0.007) compared with the TT carriers in both obese and T2DM women when adjusted for relevant covariates. ITLN1 rs2274907 polymorphism is not correlated with the risk of obesity and T2DM and not affect serum ITLN1 levels in Turkish adults. However, this polymorphism appears to be important in regulating triglyceride levels in obese and diabetic women.

Examining the effects of the CLU and APOE polymorphisms' combination on coronary artery disease complexed with type 2 diabetes mellitus

AIMS

Coronary artery disease (CAD) and type 2 diabetes mellitus (T2DM) are important and increasing public health problems. This study aimed to identify the impact of APOE and CLU gene polymorphisms on the prevalence of both diseases, along with the effect of these polymorphisms on lipid profile and glucose metabolism.

METHODS

736 CAD patients (≥50 stenosis) and 549 non-CAD subjects (≤30 stenosis) were genotyped for APOE (rs429358 and rs7412) and CLU (rs11136000) gene polymorphisms using hydrolysis probes in real-time PCR. Blood samples of the individuals were drawn before coronary angiography and biochemical analyses were done. The associations between the polymorphisms and the selected parameters were assessed using statistical analysis.

RESULTS

In this study, the ε2 and ε4 isoforms of apoE were associated with serum lipid levels and TC/HDL-C and LDL-C/HDL-C ratios in analysis adjusted for several confounders and in crude analysis. It was observed that CLU T allele carrier non-CAD subjects had lower glycosylated hemoglobin levels. Furthermore, the effects of APOE and CLU polymorphisms were assessed on CAD and T2DM presence. In crude and multiple logistic regression analyses, the ε2 isoform carriers had a lower risk for CAD complexed with T2DM. When the combinational effects of APOE and CLU polymorphisms were examined, the ε2 and T allele carriers had decreased risk for CAD complexed with T2DM compared to non-carriers.

CONCLUSIONS

In conclusion, the combination of APOE and CLU polymorphisms is associated with CAD-DM status along with the APOE ε2 isoform by itself, and the apoE isoforms are strongly associated with serum lipid levels.

Cholesterol-related gene variants are associated with diabetes in coronary artery disease patients

Coronary artery disease (CAD) which is a complex cardiovascular disease is the leading cause of death worldwide. The changing prevalence of the disease in different ethnic groups pointing out the genetic background of CAD. In this study, we aimed to evaluate the contribution of selected cholesterol metabolism-related gene polymorphisms to CAD presence. A total of 493 individuals who underwent coronary angiography were divided into 2 groups: normal coronary arteries (≤ 30% stenosis) and critical disease (≥ 50% stenosis). Individuals were genotyped for APOC1 (rs11568822), APOD (rs1568565), LIPA (rs13500), SORL1 (rs2282649), and LDLR (rs5930) polymorphisms using hydrolysis probes in Real-Time PCR. Blood samples were drawn before coronary angiography and biochemical analyses were done. The results were statistically evaluated. When the study group was stratified according to CAD, the minor allele of APOD polymorphism was found related to decreased risk for T2DM in the non-CAD group. In logistic regression analysis adjusted for several confounders, LDLR rs5930 polymorphism was found associated with T2DM presence in the male CAD group [OR = 0.502, 95%CI (0.259-0.974), p = 0.042]. Besides, APOD and LIPA polymorphisms were shown to affect serum lipid levels in non-CAD T2DM patients (p < 0.05). The minor allele of APOC1 was found associated with triglyceride levels in males independent of CAD status. Besides, LDLR minor allele carrier females had elevated HbA1c and glucose levels independent from CAD status in the whole group. The cholesterol metabolism-related gene polymorphisms were found associated with T2DM and biochemical parameters stratified to sex, CAD, and T2DM status.

The rs2175898 Polymorphism in the ESR1 Gene has a Significant Sex-Specific Effect on Obesity

Polymorphisms in the ESR1 gene have been associated with obesity and lipid metabolism. There are also important sex-related differences in the prevalence of obesity and related phenotypes. Therefore, we aimed to interrogate the association of the ESR1 rs2175898 gene polymorphism with obesity, obesity-related variables, and lipid levels in men and women as separate groups. Two thousand twenty-two randomly selected middle-aged and elderly Turks were genotyped for ESR1 rs2175898 polymorphism using real-time polymerase chain reaction with hybridization probes. We found sex-related differences of the ESR1 rs2175898 polymorphism in obesity. Logistic regression analysis after adjustment for age, smoking status, physical activity, diabetes mellitus, and the presence of menopause status in women demonstrated significantly decreased risk for obesity in female AG genotype carriers (OR 0.69; 95% CI 0.52-0.91; p = 0.010), and in male GG genotype carriers (OR 0.49; 95% CI 0.25-0.96; p = 0.039), Furthermore, carriers of the rs2175898 G allele exhibited a lower body mass index in both sexes and decreased waist circumference in women but not in men. Our findings also showed significantly higher serum total-C levels (p = 0.007) in the carriers of the AG+GG/AG genotype compared with the AA genotype in men. The AG genotype of the ESR1 rs2175898 polymorphism in women and GG genotype in men were found to have a decreased likelihood for obesity compared with the other rs2175898 genotypes.

A patient with early-onset Alzheimer's disease with a novel PSEN1 p.Leu424Pro mutation

"Presenilin 1" (PSEN1) gene mutations are the major known genetic cause of early-onset Alzheimer's disease. Herein, we report a novel heterozygous PSEN1 mutation (p.Leu424Pro) in a Turkish patient presenting with deterioration of short-term memory and visuospatial skills starting at the age of 47 years. This novel mutation is located in the conserved residue of transmembrane domain 8 coded by exon 12. At the protein level, this mutation caused a disruption in the alpha helix structure of PSEN1. The structural and possible functional consequences of the mutation suggest that it has probably a pathogenic effect, which in turns had a potential role in the development of Alzheimer's disease in our patient.

HPCA confirmed as a genetic cause of DYT2-like dystonia phenotype

BACKGROUND

HPCA (hippocalcin) is one of the underlying genetic causes of autosomal-recessively inherited forms of dystonia. Here, we describe two consanguineous Turkish DYT-HPCA families carrying the novel HPCA mutations.

METHODS

After detailed clinical and neurological examination, whole-exome sequencing was performed.

RESULTS

Whole-exome sequencing analysis revealed two homozygous novel truncating mutations (p.W103* and p.P10PfsTer80) in the HPCA gene in two unrelated Turkish dystonia families presenting with complex dystonia.

CONCLUSIONS

After identification of HPCA as a genetic cause of DYT-HPCA-like dystonia by Charlesworth et al, this is the second report in the scientific literature that describes dystonia families harboring HPCA mutations. Our findings confirm that HPCA leads to recessively inherited dystonia. © 2018 International Parkinson and Movement Disorder Society.

Role of LRRK2 and SNCA in autosomal dominant Parkinson's disease in Turkey

INTRODUCTION

Mutations in the LRRK2 and alpha-synuclein (SNCA) genes are well-established causes of autosomal dominant Parkinson's disease (PD). However, their frequency differs widely between ethnic groups. Only three studies have screened all coding regions of LRRK2 and SNCA in European samples so far. In Turkey, the role of LRRK2 in Parkinson's disease has been studied fragmentarily, and the incidence of SNCA copy number variations is unknown. The purpose of this study is to determine the frequency of LRRK2 and SNCA mutations in autosomal dominant PD in Turkey.

METHODS

We performed Sanger sequencing of all coding LRRK2 and SNCA exons in a sample of 91 patients with Parkinsonism. Copy number variations in SNCA, PRKN, PINK1, DJ1 and ATP13A2 were assessed using the MLPA method. All patients had a positive family history compatible with autosomal dominant inheritance.

RESULTS

Known mutations in LRRK2 and SNCA were found in 3.3% of cases: one patient harbored the LRRK2 G2019S mutation, and two patients carried a SNCA gene duplication. Furthermore, we found a heterozygous deletion of PRKN exon 2 in one patient, and four rare coding variants of unknown significance (LRRK2: A211V, R1067Q, T2494I; SNCA: T72T). Genetic testing in one affected family identified the LRRK2 R1067Q variant as a possibly pathogenic substitution.

CONCLUSION

Point mutations in LRRK2 and SNCA are a rare cause of autosomal dominant PD in Turkey. However, copy number variations should be considered. The unclassified variants, especially LRRK2 R1067Q, demand further investigation.

Mutations in TYROBP are not a common cause of dementia in a Turkish cohort

Mutations in TYROBP and TREM2 have been shown to cause polycystic lipomembranous osteodysplasia with sclerosing leukoencephalopathy. Recently, variants in TREM2 were also associated with frontotemporal dementia and Alzheimer's disease. Given the functional proximity between these 2 genes, we investigated the genetic variation of TYROBP in a Turkish cohort of 103 dementia patients. No mutations or copy number variants predicted to be pathogenic were identified. These results indicate that mutations in TYROBP are not a common cause of dementia in this Turkish cohort.

Loss of VPS13C Function in Autosomal-Recessive Parkinsonism Causes Mitochondrial Dysfunction and Increases PINK1/Parkin-Dependent Mitophagy

Autosomal-recessive early-onset parkinsonism is clinically and genetically heterogeneous. The genetic causes of approximately 50% of autosomal-recessive early-onset forms of Parkinson disease (PD) remain to be elucidated. Homozygozity mapping and exome sequencing in 62 isolated individuals with early-onset parkinsonism and confirmed consanguinity followed by data mining in the exomes of 1,348 PD-affected individuals identified, in three isolated subjects, homozygous or compound heterozygous truncating mutations in vacuolar protein sorting 13C (VPS13C). VPS13C mutations are associated with a distinct form of early-onset parkinsonism characterized by rapid and severe disease progression and early cognitive decline; the pathological features were striking and reminiscent of diffuse Lewy body disease. In cell models, VPS13C partly localized to the outer membrane of mitochondria. Silencing of VPS13C was associated with lower mitochondrial membrane potential, mitochondrial fragmentation, increased respiration rates, exacerbated PINK1/Parkin-dependent mitophagy, and transcriptional upregulation of PARK2 in response to mitochondrial damage. This work suggests that loss of function of VPS13C is a cause of autosomal-recessive early-onset parkinsonism with a distinctive phenotype of rapid and severe progression.

Clinical variability in ataxia-telangiectasia

Ataxia-telangiectasia (A-T) is an autosomal recessive inherited disease characterized by progressive childhood-onset cerebellar ataxia, oculomotor apraxia, choreoathetosis and telangiectasias of the conjunctivae. Further symptoms may be immunodeficiency and frequent infections, and an increased risk of malignancy. As well as this classic manifestation, several other non-classic forms exist, including milder or incomplete A-T phenotypes caused by homozygous or compound heterozygous mutations in the ATM gene. Recently, ATM mutations have been found in 13 Canadian Mennonites with early-onset, isolated, predominantly cervical dystonia, in a French family with generalized dystonia and in an Indian family with dopa-responsive cervical dystonia. In this article, we will describe a Turkish family with three affected sibs. Their phenotypes range from pure cervical dystonia associated with hand tremor to truncal and more generalized dystonic postures. Exome sequencing has revealed the potentially pathogenic compound heterozygous variants p.V2716A and p.G301VfsX19 in the ATM gene. The variants segregated perfectly with the phenotypes within the family. Both mutations detected in ATM have been shown to be pathogenic, and the α-fetoprotein, a marker of ataxia telangiectasia, was found to be increased. This report supports recent literature showing that ATM mutations are not exclusively associated with A-T but may also cause a more, even intra-familial variable phenotype in particular in association with dystonia.

Oxidative stress-mediated (sex-specific) loss of protection against type-2 diabetes by macrophage migration inhibitory factor (MIF)-173G/C polymorphism

BACKGROUND

The archetypical yet atypical cytokine macrophage migration inhibitory factor (MIF) fulfills pleiotropic immune functions in inflammatory diseases. Evidence emerging from both expression and functional studies implicates MIF in various aspects of cardiovascular diseases. We aimed to determine the covariates of MIF-173G/C polymorphism and its influence on type-2 diabetes risk in a sample representative of middle-aged Turks.

METHODS

Randomly selected 2250 Turkish adults (mean age; 49.7±11.9, 48.5% male) were genotyped for -173G/C polymorphism using hybridization probes in Real-Time PCR LC480 device.

RESULTS

The MIF-173CC genotype prevailed in 3.7% in men and 2.9% in women. C-allele carriage was associated linearly with wider waist girth, independently of fasting glucose, and was further related to higher apolipoprotein B (apoB) (p<0.05) in men, but not women. Logistic regression analysis showed the C-allele carriage to tend to predict new-onset diabetes (RR 1.51; [95% CI 0.98; 2.32]), additively to age and fasting glucose in men, but not in women. In contrast, risk for established (baseline) diabetes mellitus was lower (OR=0.49, 95% Cl 0.26-0.93, p=0.03) in heterozygotes, after adjustment for atherogenic dyslipidemia and other confounders.

CONCLUSION

MIF-173GC polymorphism independently contributes to abdominal obesity and is related to apoB concentrations apparently in men alone. Tendency of the -173C-allele carriage to predict new-onset diabetes independently was also confined to men. These gender-modulated associations suggest novel gene-gender-environmental interactions originating from a proinflammatory state.

Gender-specific associations of the APOA1 -75G>A polymorphism with several metabolic syndrome components in Turkish adults

BACKGROUND

Variations in the apolipoprotein A-1 (APOA1) gene, a determinant of plasma high-density lipoprotein cholesterol (HDL-C) and apoA-I levels, may contribute to cardiovascular diseases. We evaluated the effects of a promoter polymorphism (-75G>A) in the APOA1 gene on metabolic syndrome (MetS) components in a Turkish population sample.

METHODS

Randomly selected 1515 Turkish adults (age 49.9±11.8 years, 785 females) were genotyped for -75G>A polymorphism using hybridization probes in Real-Time PCR LC480 device. MetS and atherogenic dyslipidemia were defined using the criteria of ATP III.

RESULTS

The -75AA genotype prevailed in 3.9% of men and 2.4% of women, and was independently associated with significantly higher HDL-C concentrations. Independent associations with the -75GA genotype existed only in men: higher diastolic and systolic blood pressure (BP) levels (p<0.05) were observed in male -75GA heterozygotes. Logistic regression revealed that the GA genotype confers elevated risk for atherogenic dyslipidemia (OR=1.57, 95% Cl 1.06-2.3) after adjustment for associated risk factors. Independent associations with atherogenic dyslipidemia or elevated BP did not emerge in women.

CONCLUSION

APOA1 -75G>A polymorphism is independently related to HDL-C concentrations. Independent associations of the -75GA genotype with elevated BP and atherogenic dyslipidemia were confined to men. These gender-modulated associations suggest novel gene-gender-environmental interactions.

Identification of PSEN1 and PSEN2 gene mutations and variants in Turkish dementia patients

In order to assess the frequency of mutations in the known Alzheimer's disease causative genes in Turkish dementia patients we screened amyloid precursor protein (APP), PSEN1 and PSEN2 for mutations in a cohort of 98 Turkish dementia families. Six families were found to carry PSEN1 mutations (p.H163R, p.P264L, and p.H214Y) or variants suggested to cause the disease (p.L134R, p.L262V, and p.A396T). In 4 other families, previously reported PSEN2 variants were identified (p.R62H, p.R71W, p.M174V (n = 2), and p.S130L). The phenotype of the carriers varied from rapid progressing Alzheimer's disease to frontotemporal dementia, with spasticity and seizures also observed. Here we report a frequency of 11.2% of mutations and variants in the known Alzheimer disease genes in the dementia cohort studied and 24% in the early onset subgroup of patients, suggesting that mutations in these genes are not uncommon in Turkey and are associated with various phenotypes. We thus believe that genetic analysis should become a standardized diagnostic implement, not only for the identification of the genetic disease, but also for appropriate genetic counseling.

Isolation and analysis of genes mainly expressed in adult mouse heart using subtractive hybridization cDNA library

Subtractive hybridization cDNA library (SHL) is one of the powerful approaches for isolating differentially expressed genes. Using this technique between mouse heart and skeletal muscle (skm) tissues, we aimed to construct a cDNA-library that was specific to heart tissue and to identify the potential candidate genes that might be responsible for the development of cardiac diseases or related pathophysiological conditions. In the first step of the study, we created a cDNA-library between mouse heart and skm tissues. The homologies of the randomly selected 215 clones were analyzed and then classified by function. A total of 146 genes were analyzed for their expression profiles in the heart and skm tissues in published mouse microarray dataset. In the second step, we analyzed the expression patterns of the selected genes by Northern blot and RNA in situ hybridization (RISH). In Northern blot analyses, the expression levels of Myl3, Myl2, Mfn2, Dcn, Pdlim4, mt-Co3, mt-Co1, Atpase6 and Tsc22d1 genes were higher in heart than skm. For first time with this study, expression patterns of Pdlim4 and Tsc22d1 genes in mouse heart and skm were shown by RISH. In the last step, 43 genes in this library were identified to have relationships mostly with cardiac diseases and/or related phenotypes. This is the first study reporting differentially expressed genes in healthy mouse heart using SHL technique. This study confirms our hypothesis that tissue-specific genes are most likely to have a disease association, if they possess mutations.

Gender- and obesity-specific effect of apolipoprotein C3 gene (APOC3) -482C>T polymorphism on triglyceride concentration in Turkish adults

BACKGROUND

Apolipoprotein C3 (APOC3) gene polymorphisms are associated with cardiometabolic risk factors, varying in ethnicities. This study aimed to investigate such association between the APOC3 -482C>T polymorphism and cardiometabolic risk factors in the turkish adult risk factor (TARF) study cohort, stratifying by gender and obesity.

METHODS

Randomly selected 1548 individuals (757 male and 791 female, mean age 49.9±11.8 years) were genotyped for -482C>T polymorphism using hybridization probes in a Real-Time PCR LC480 device.

RESULTS

The -482TT genotype prevailed 9.9% in men and 11.5% in women. Association between 482C>T polymorphism and dyslipidemia (p=0.036, OR=1.42, 95%Cl=1.02-1.97) was found only in men. Analysis of variance showed that anthropometric and metabolic variables were not differently distributed in APOC3 -482C>T genotypes in the study population. In relation to dyslipidemia and obesity, the -482C>T polymorphism showed significant gender-by-genotype interactions (p<0.01). When the study population was stratified according to gender and obesity, homozygotes for the T allele were associated strongly with (by 45%) elevated fasting triglyceride concentrations in obese men (p=0.009) and homeostatic model assessment (HOMA) index in non-obese women (p=0.013). Furthermore, in the same subgroups, the associations of the fasting triglyceride concentrations and HOMA index with the TT genotype remained after adjustment for risk factors (p<0.05).

CONCLUSIONS

APOC3 -482TT genotype is independently associated with elevated fasting triglyceride concentrations in obese men. Presence of obesity seems to be required for this genotype to induce markedly elevated triglycerides. Furthermore, it is associated with the dyslipidemia in men, without requirement of obesity.

The APOE -219G/T and +113G/C polymorphisms affect insulin resistance among Turks

The -219G/T (rs405509) and +113G/C (rs440446) polymorphisms within the regulatory region of the apolipoprotein E (APOE) gene have been related to the transcriptional activity of the gene. We examined the effect of the stated polymorphisms and their construct haplotypes with the APOE ɛ2/ɛ3/ɛ4 polymorphism on lipid levels and insulin resistance in the Turkish Adult Risk Factor Study. Randomly selected 1774 adults (mean age, 55.0 ± 11.7 years; 51.2% women) participating in the population-based Turkish Adult Risk Factor Study were cross-sectionally analyzed for the -219G/T, +113G/C, and ɛ2/ɛ3/ɛ4 polymorphisms as well as their haplotypes. Insulin resistance was defined as the 70th percentile in the sample (>2.51) of the homeostatic model assessment (HOMA). The frequencies of the -219T and +113C alleles were 0.477 and 0.423, respectively; and those of haplotype 1 (GGɛ3) and haplotype 2 (TCɛ3) were 44.1% and 41.9%, respectively. The -219G/T and +113G/C genotypes (both P < .04) and diplotypes of haplotype 2 (TCɛ3) (P < .014) were inversely related to serum fasting insulin and the HOMA index, even after controlling for 8 relevant covariates, but not to serum lipids. Within the APOE3 group, haplotype 2 (TC-/TC+) heterozygotes had an odds ratio of 0.66 (95% confidence interval, 0.42-0.99) for HOMA of insulin resistance after adjusting for 8 covariates. APOE promoter polymorphisms and their diplotypes are independently related with serum fasting insulin levels and HOMA index among Turks.

Endothelial function and endothelial nitric oxide synthase intron 4a/b polymorphism in primary hyperparathyroidism

BACKGROUND AND AIM

Patients with symptomatic primary hyperparathyroidism (pHT) have increased cardiovascular morbidity and mortality. Endothelial nitric oxide synthase (eNOS) intron 4a/b polymorphism is associated with coronary artery disease and hypertension in various populations. Our aim is to evaluate endothelial function in patients with pHT during pre-operative hypercalcemic and post-operative normocalcemic periods and to determine whether intron 4a/b polymorphism of eNOS gene influences endothelial function.

SUBJECTS AND METHODS

Forty patients with pHT (age 48.48+/-11.64 yr) were examined pre-operatively and reexamined 5.8+/-1.9 months after parathyroidectomy. Forty-three healthy subjects (age 47.13+/-8.14 yr) were served as control group. Endothelial function was determined by flow-mediated dilation of brachial artery (FMD). eNOS4a/b polymorphism was detected by polymerase chain reaction.

RESULTS

FMD was significantly lower in patients pre-operatively compared with controls (8.48+/-1.78% vs 19.49+/-2.34%, p<0.001). FMD improved significantly after parathyroidectomy (16.19+/-2.16%, p<0.001 compared with pre-operative measurements), but was still significantly lower than controls (p<0.001). The distribution of eNOS4a/b genotype frequencies was not significantly different between patients and controls. Logistic regression analysis showed that increased serum calcium (>2.47 mmol/l) and PTH concentrations (>7.75 pmol/l) were significant independent predictors of lower FMD (<16.7%). ENOS4a/b polymorphism did not enter in this model.

CONCLUSION

Impaired endothelial function in patients with pHT improves after successful parathyroid surgery. No compelling data are evident to suggest that eNOS4a/b polymorphism modifies the endothelial function in patients with pHT.

ADAM-9, ADAM-15, and ADAM-17 are upregulated in macrophages in advanced human atherosclerotic plaques in aorta and carotid and femoral arteries--Tampere vascular study

BACKGROUND AND AIMS

The expression of disintegrin and metalloprotease ADAM-9, ADAM-15, and ADAM-17 has been associated with cell-cell, cell-platelet, and cell-matrix interactions and inflammation. They are possibly implicated in the pathophysiology of atherosclerosis.

METHODS AND RESULTS

Whole-genome expression array and quantitative real-time polymerase chain reaction (PCR) analysis confirmed that ADAM-9, ADAM-15, and ADAM-17 are upregulated in advanced human atherosclerotic lesions in samples from carotid, aortic, and femoral territories compared to samples from internal thoracic artery (ITA) free of atherosclerotic plaques. Western analysis indicated that the majority of these ADAMs were in the catalytically active form. ADAM-9, ADAM-15, and ADAM-17-expressing cells were shown to co-localize with CD68-positive cells of monocytic origin in the atherosclerotic plaques using immunohistochemistry and double-staining immunofluorescence analysis. Co-localization was demonstrated in all vascular territories. In the carotid territory, cells expressing the ADAMs co-distributed also with smooth muscle cells and, in femoral territory, with CD31-positive endothelial cells, indicating that the ADAM expression pattern depends on vascular bed territory.

CONCLUSIONS

Present findings provide strong evidence for the involvement of catalytically active ADAM-9, ADAM-15, and ADAM-17 in advanced atherosclerosis, most notably associated with cells of monocytic origin.

A novel protein involved in heart development in Ambystoma mexicanum is localized in endoplasmic reticulum

The discovery of the naturally occurring cardiac non-function (c) animal strain in Ambystoma mexicanum (axolotl) provides a valuable animal model to study cardiomyocyte differentiation. In homozygous mutant animals (c/c), rhythmic contractions of the embryonic heart are absent due to a lack of organized myofibrils. We have previously cloned a partial sequence of a peptide cDNA (N1) from an anterior-endoderm-conditioned-medium RNA library that had been shown to be able to rescue the mutant phenotype. In the current studies we have fully cloned the N1 full length cDNA sequence from the library. N1 protein has been detected in both adult heart and skeletal muscle but not in any other adult tissues. GFP-tagged expression of the N1 protein has revealed localization of the N1 protein in the endoplasmic reticulum (ER). Results from in situ hybridization experiments have confirmed the dramatic decrease of expression of N1 mRNA in mutant (c/c) embryos indicating that the N1 gene is involved in heart development.

Genetic analysis of the Irx4 gene in hypertrophic cardiomyopathy

OBJECTIVES

The Irx4 gene is predominantly expressed in cardiac ventricles. It has been demonstrated in animal studies that disruption of the Irx4 gene causes inhibition of chamber-specific expression of myosin heavy chain genes, resulting in abnormal ventricular gene expression and cardiac hypertrophy. In this study, we aimed to investigate a possible association between mutations in the Irx4 gene and hypertrophic cardiomyopathy (HC).

STUDY DESIGN

The study included 68 patients (32 females, 36 males; mean age 49 years; range 17 to 74 years) with HC and 67 healthy controls (33 females, 34 males; mean age 45 years; range 20 to 88 years). All the patients were evaluated with a detailed history, physical examination, 12-lead electrocardiography, and transthoracic echocardiography. DNA samples of all the subjects were extracted. Genomic DNA fragments were amplified by polymerase chain reaction and screened by single-strand conformation polymorphism analysis. DNA sequences were determined through an automated sequencing system.

RESULTS

All exons in the Irx4 gene were examined. No mutations were detected associated with HC. Four polymorphisms were identified including G355>A, A381>G, G1203>A, and C1431>T. Compared with patients having the GA and GG genotyes, patients with the AA genotype of A381>G polymorphism were found to have a higher maximal left ventricle outflow tract gradient (p=0.03), prolonged corrected QT dispersion (p=0.05), and albeit not statistically significant, increased septal thickness (p=0.07).

CONCLUSION

This is the first human study investigating the association between the Irx4 gene and HC. Polymorphism A381>G of the Irx4 gene may have a modifier effect on septal thickness, resulting in increased corrected QT dispersion and higher outflow gradients.

The S447X variant of lipoprotein lipase gene is associated with metabolic syndrome and lipid levels among Turks

BACKGROUND

We evaluated the relationship of the lipoprotein lipase (LPL) S447X variant with serum lipid levels and the metabolic syndrome (MS) in the Turkish Adult Risk Factor (TARF) study. This is the first study examining this LPL variant in the Turkish population.

METHODS

The sample comprised 1586 Turkish adults. Genotyping was performed using the Taqman allelic discrimination assay.

RESULTS

The X447 allele frequency was 0.11 (95% CI: 0.10-0.12). X447 allele carriers had significantly higher levels of HDL-C, LDL-C and total cholesterol; and lower fasting glucose, when compared with the SS genotype in females. In men, no significant association with any parameters was seen. The genotypic impact of the S447X variant on lipid levels appears to be modulated by environmental factors, such as cigarette smoking in women. Logistic regression analysis demonstrated a significantly reduced likelihood for metabolic syndrome in female X447 allele carriers (p=0.04), after adjustment for age, cigarette smoking, alcohol usage and physical activity grade.

CONCLUSIONS

In especially Turkish women, compared to non-carriers, carriers of the LPL X447 allele have higher levels of HDL-C, LDL-C and total cholesterol, and show a degree of protection against developing the metabolic syndrome.

Ventricular pre-excitation and cardiac hypertrophy mimicking hypertrophic cardiomyopathy in a Turkish family with a novel PRKAG2 mutation

BACKGROUND

Mutations in PRKAG2, the gene for the gamma2 regulatory subunit of AMP-activated protein kinase, cause cardiac hypertrophy and electrophysiological abnormalities. We identified a novel mutation in PRKAG2 causing familial ventricular pre-excitation and severe cardiac hypertrophy.

METHODS AND RESULTS

We studied 30 members of one family and 120 healthy controls. Molecular analysis of PRKAG2 gene revealed one missense mutation in exon 14 which was confirmed by restriction enzyme digestion. We identified a G to A transition, resulting in a Glu506Lys substitution in the PRKAG2 gene in 8 of the family members, who all had cardiac hypertrophy and ventricular pre-excitation. High incidence of right ventricular hypertrophy and left ventricular outflow tract obstruction are other prominent features of this novel PRKAG2 mutation. Family members without mutation had no cardiac disease. The 120 unrelated healthy individuals did not show this mutation.

CONCLUSIONS

Coexistence of unexplained ventricular hypertrophy and pre-excitation should prompt the diagnosis of PRKAG2 mutations and these patients should be referred for genetic analysis. The possible alteration of AMP-activated protein kinase activity due to genetic defects in PRKAG2 may serve as a template for developing more specific therapies in the treatment of patients with this mutation.

Glycoprotein Ia 807TT/873AA genotype is not associated with myocardial infarction

OBJECTIVE

The glycoprotein Ia/IIa complex is a major platelet collagen receptor. Its surface expression is influenced by two linked single nucleotide polymorphisms (C807T and G873A) in the glycoprotein Ia (GPIa) gene. In this study we aimed to determine the frequency of GPIa C807T/G873A genotype in patients with myocardial infarction (MI) and healthy controls in Turkish population and association between these dimorphisms and risk factors of MI.

METHODS

We examined GPIa (C807T/G873A) genotypes in 158 patients with MI and 145 healthy controls. Distributions of the C807T and G873A dimorphisms were investigated by genotyping DNA using multiplexed allele-specific PCR.

RESULTS

There was no association between GPIa genotypes and MI. We further analysed each group for all known risk factors such as plasma lipid levels, cigarette smoking, diabetes, hypertension, gender, age, MI history and body mass index. When compared with other two genotypes for glycoprotein Ia (GT/GA and CC/GG), TT/AA showed an association with higher high-density lipoprotein (HDL) -cholesterol levels in the healthy control group, but none in the group with MI.

CONCLUSION

The 807TT/873AA genotype of the GPIa gene alone or in combination with risk factors had no major effect on MI, however, it appears to be associated with higher HDL-cholesterol levels in healthy subjects.

Van Der Woude syndrome: variable penetrance of a novel mutation (p.Arg 84Gly) of the IRF6 gene in a Turkish family

Van der Woude syndrome (VWS) is an autosomal dominant disorder characterized by clefts of the lip and/or palate (CL+/-P), lip pits, bifid uvula and hypodontia. Mutations of the interferon regulatory factor 6 gene (IRF6) have been recently described in patients with VWS. The entire 9 exons of the IRF6 gene in two brothers of Turkish origin clinically diagnosed with Van der Woude syndrome and four healthy family members were screened for mutations using a newly established denaturing gradient gel electrophoresis (DGGE) method. A novel heterozygous mutation in exon 2 (DNA binding region) of the IRF6 gene, p.Arg84Gly, was found in both brothers with VWS and in their clinically asymptomatic mother. Our results suggest a dominant negative effect of the p.Arg84Gly mutation in the VWS of both patients. Non-penetrance of this mutation is suggested in the mother of the patients.