DNA variants at the genes encoding cardiac channels have been associated with inherited arrhythmias and the QT interval in the general population. Next generation sequencing technologies would be of ...special interest to uncover the genetic variation at these genes. The amplification and sequencing of DNA pools (instead of single individuals) would facilitate the rapid and cost-effective screening of large amounts of individuals. However, this pooling strategy could result in a signal of the rare variants below the detection capacity. To validate this approach, a pool of 20 individuals with known rare unique variants in five genes was amplified in only two tubes and sequenced using the non optical semi-conductor (
Ion Torrent PGM
, Life Technologies) technology. We show that this could be an effective strategy for the screening of large cohorts. Among others, this would facilitate the discovery of new sequence variants linked to cardiac arrhythmia in the general population.
MicroRNAs (miRNAs) are small RNAs that bind to mRNAs and regulate gene expression. MyoMirs are miRNAs implicated in cardiogenesis. Some MyoMirs have been found deregulated in hearts from patients ...with left ventricular hypertrophy (LVH). DNA variants at these miRNAs could contribute to the risk of developing hypertrophic cardiomyopathy (HCM). To test this hypothesis we used single strand conformation analysis and direct sequencing to search for DNA variants in the mir-208a, miR-208b, miR-133a-1, miR-133a-2, miR-133b, miR-1-1, and miR-1-2 genes in patients with HCM (n=245), LVH secondary to hypertension (n=120), and healthy controls (n=250). We found several nucleotide variants. Genotyping of patients and healthy controls showed significantly associations between a 133a-1 polymorphism and HCM and a 133b polymorphism and hypertensive- LVH. We concluded that rare variants in these mature miRNAs would be rarely found among HCM patients, but miR-133a-1 and 133b polymorphisms could contribute to the risk of developing cardiac hypertrophy.
In order to determine the role of two polymorphisms in the factor VII gene (R353Q and intron 7 hypervariable region) in the susceptibility to develop early myocardial infarction, a total of 175 ...patients with acute myocardial infarction aged 50 years or less (mean age 41±7 years) and 200 controls (average age 42±6) without cardiovascular disease were genotyped for these polymorphisms. Gene and genotype frequencies did not differ between patients and controls. Although the 353-QQ genotype was at a higher frequency among controls (4%) compared to patients (1%), the difference did not reach statistical significance. Carriers of the H7-allele (intron 7 polymorphism) were at a slightly higher frequency among patients (51 vs. 43%;
P=0.19; OR=1.36; 95% CI=1.09–1.70). Our data suggest a lack of association between both polymorphisms in the factor VII gene and early myocardial infarction in our population.
Abstract Introduction and objectives Hypertrophic cardiomyopathy (HCM) is the most common inherited cardiac disease. The current challenge relies on the accurate classification of the pathogenicity ...of the variants. Transthoracic echocardiography (TTE) is recommended at initial evaluation and cardiac magnetic resonance (CMR) imaging should also be considered. We aimed to reappraise the penetrance and clinical expression of the MYBPC3 p.G263* variant. Methods Three hundred and eighty-four HCM probands and a control cohort of 450 individuals were studied for the main sarcomere genes by next-generation sequencing. All MYBPC3 p.G263* carriers were identified and family screening was performed. Clinical information was recorded retrospectively before 2015 and prospectively thereafter. Extra effort was invested in performing CMR in all carriers, despite TTE results. Results Thirteen HCM probands and none of the controls were carriers of the MYBPC3 p.G263* pathogenic variant (according to the American College of Medical Genetics and Genomics and the Association for Molecular Pathology). A total of 39 carriers were identified with family screening. Most patients with HCM were asymptomatic at the time of diagnosis and showed late-onset disease. Despite having a relatively benign course in the young, late HCM-related complications could occur. Penetrance was around 70% when evaluated by TTE and was 87.2% with TTE plus CMR. Penetrance was age-dependent, reaching 100% in carriers older than 55 years. Conclusions MYBPC3 p.G263* shares with most truncating pathogenic variants in this gene a late onset, relatively benign clinical course in the young, and high penetrance. Cardiac magnetic resonance could be a useful tool to evaluate carriers despite TTE results.
Inherited and acquired risk factors contribute to the development of the atherosclerotic lesion and its most common clinical manifestation, myocardial infarction (MI). Multiple studies have suggested ...a role for matrix metalloproteinases (MMPs) in atherosclerosis, and several functional polymorphisms in the MMP-1 gene have been linked to the risk of MI. The aim of this study was to evaluate the association between MMP-1 promoter polymorphisms and early MI in a Spanish cohort.
We carried out a case-control study with 261 unrelated patients who had suffered an MI before 55 years of age and 194 healthy controls, all male and smokers. The genotypes for the three MMP-1 promoter polymorphisms -1607 1G/2G, -519 A/G, and -340 T/C were determined through PCR-restriction fragment length polymorphism. Allelic, genotypic, and haplotypic frequencies were statistically compared between groups.
Frequencies of the three polymorphisms did not differ between patients and controls. The -1607 1G/2G and -519 A/G variants were in linkage disequilibrium. Analysis of the haplotype frequencies showed significant associations of the 2G(-1607)-G(-519)-T(-340) (odds ratio = 2.40; 95% confidence interval = 1.27-4.55; P<0.006) and 1G(-1607)-G(-519)-T(-340) (odds ratio = 0.68; 95% confidence interval = 0.50-0.94; P<0.05) haplotypes with the risk of early MI.
MMP-1 promoter polymorphisms are associated with the risk of early MI in a Spanish population of smoking males.
A single nucleotide polymorphism (SNP) in chromosome Y has been associated with blood pressure. In men, the risk of suffering from cardiovascular diseases, including coronary artery disease, could be ...influenced by one or more loci on chromosome Y. We genotyped 208 men who had suffered an early episode of myocardial infarction (MI) (< or =55 years) and 178 healthy control men for two Y-polymorphisms (a HindIII polymorphism in an alphoid satellite in the centromeric non-recombining region and the -2627 T/C in the SRY gene). Frequencies were compared through a chi(2)-test. Frequencies for the two polymorphisms did not differ between patients and controls. The alphoid-HindIII polymorphism was not related to blood pressures in our population (HindIII+: diastolic, 80 +/- 2; systolic, 129 +/- 5. HindIII-: diastolic, 80 +/- 2; systolic, 128 +/- 3). Seventy-six patients (37%) were hypertensives and had a significantly higher frequency of the HindIII+ allele compared to the normotensive patients (46 and 26%, respectively; P = 0.028). According to our data, the alphoid-HindIII polymorphism in chromosome Y was not associated with differences in blood pressure in men from Asturias (Northern Spain). However, the HindIII+ allele increased the risk of suffering an early episode of MI among hypertensives.
Abstract We sequenced the coding exons of the cardiac troponins T (TNNT2) and I (TNNI3) genes in 115 Spanish HCM-patients (32% with a family history of the disease). Only two (2%) had mutations in ...the TNNT2 (Arg278 > Cys and Arg92 > Lys). These mutations were associated with variable clinical outcomes. No patient had TNNI3-mutation. We also genotyped these patients and 320 healthy controls for a 5 bp insertion/deletion (I/D) polymorphism in intron 3 of TNNT2. DD-homozygotes for the 5 bp I/D polymorphism were significantly more frequent among the patients (OR = 1.83, 95% CI = 2.10–5.16).
The long noncoding RNA
and its host micro RNA miR-675 have been found deregulated in cardiac hypertrophy and heart failure tissues. Our aim was to investigate whether the
gene variants were ...associated with the risk of hypertrophic cardiomyopathy (HCM).
We genotyped two
tag single nucleotide polymorphisms in 405 HCM patients and 550 controls, and sequenced this gene in 100 patients.
The rs2107425 C was significantly increased in sarcomere no-mutation patients (n = 225; p = 0.01): CC versus CT + TT, p = 0.017; odd ratios: 1.51. Sequencing of the
coding transcript identified two patients heterozygous carriers for a rare variant, rs945977096 G/A, that was absent among the controls.
Our study suggested a significant association between
variants and the risk of developing HCM.
To examine the association between coronary artery disease and polymorphisms at the angiotensin-converting enzyme (ACE) and angiotensin II type 1 receptor (AT1R) genes.
A total of 181 patients ...younger than 50 years and 240 controls from the same homogeneous Caucasian population (Asturias, Northern Spain) were genotyped (using polymerase chain reaction) for the ACE insertion/deletion (ACE-I/D) and the AT1R A/C transversion (AT1R-A/C) (3-untranslated region) polymorphisms.
The DD-genotype was at a non-significant higher frequency among patients (50%) than in controls (41%). No difference between the two groups was found for the AT1R-genotypes. Distribution of ACE-genotypes according to AT1R-genotypes showed a significant association between ACE-DD and AT1R-CC and early coronary disease. Among the CC patients 58% were DD, compared to 21% among the controls (p = 0.02; OR = 5.32, 95% CI = 1.45, 19.51). We determined the distribution of these genotypes among the hypertensive and non-hypertensive patients. Frequencies of ACE- or AT1R-genotypes did not differ between the two groups. However, we found an interaction between the DD- and CC-genotypes in the group of normotensives. Among the CC patients, 13% of the hypertensives and 75% of the normotensives were DD (p = 0.014).
Our results indicate a synergistic contribution of ACE and AT1R polymorphisms to the risk of coronary artery disease. This gene-gene interaction could have clinical implications. Approximately 2% of individuals in our population are CC + DD, and the genotyping of both polymorphisms could identify those with a high relative risk for coronary artery disease.
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