Novel genes and sex differences in COVID-19 severity.

Here, we describe the results of a genome-wide study conducted in 11 939 coronavirus disease 2019 (COVID-19) positive cases with an extensive clinical information that were recruited from 34 hospitals across Spain (SCOURGE consortium). In sex-disaggregated genome-wide association studies for COVID-19 hospitalization, genome-wide significance (P < 5 × 10-8) was crossed for variants in 3p21.31 and 21q22.11 loci only among males (P = 1.3 × 10-22 and P = 8.1 × 10-12, respectively), and for variants in 9q21.32 near TLE1 only among females (P = 4.4 × 10-8). In a second phase, results were combined with an independent Spanish cohort (1598 COVID-19 cases and 1068 population controls), revealing in the overall analysis two novel risk loci in 9p13.3 and 19q13.12, with fine-mapping prioritized variants functionally associated with AQP3 (P = 2.7 × 10-8) and ARHGAP33 (P = 1.3 × 10-8), respectively. The meta-analysis of both phases with four European studies stratified by sex from the Host Genetics Initiative (HGI) confirmed the association of the 3p21.31 and 21q22.11 loci predominantly in males and replicated a recently reported variant in 11p13 (ELF5, P = 4.1 × 10-8). Six of the COVID-19 HGI discovered loci were replicated and an HGI-based genetic risk score predicted the severity strata in SCOURGE. We also found more SNP-heritability and larger heritability differences by age (<60 or ≥60 years) among males than among females. Parallel genome-wide screening of inbreeding depression in SCOURGE also showed an effect of homozygosity in COVID-19 hospitalization and severity and this effect was stronger among older males. In summary, new candidate genes for COVID-19 severity and evidence supporting genetic disparities among sexes are provided.

The genetic component of bicuspid aortic valve and aortic dilation. An exome-wide association study.

BACKGROUND: Bicuspid aortic valve is the most common cardiovascular congenital malformation affecting 2% of the general population. The incidence of life-threatening complications, the high heritability, and familial clustering rates support the interest in identifying risk or protective genetic factors. The main objective of the present study was to identify population-based genetic variation associated with bicuspid aortic valve and concomitant ascending aortic dilation. MATERIALS AND METHODS: A cross-sectional exome-wide association study was conducted in 565 Spanish cases and 484 controls. Single-marker and gene-based association analyses enriched for low frequency and rare genetic variants were performed on this discovery stage cohort and for the subsets of cases with and without ascending aortic dilation. Discovery-stage association signals and additional markers indirectly associated with bicuspid aortic valve, were genotyped in a replication cohort that comprised 895 Caucasian cases and 1483 controls. RESULTS: Although none of the association signals were consistent across series, the involvement of HMCN2 in calcium metabolism and valve degeneration caused by calcium deposit, and a nominal but not genome-wide significant association, supported it as an interesting gene for follow-up studies on the genetic susceptibility to bicuspid aortic valve. CONCLUSIONS: The absence of a genome-wide significant association signal shows this valvular malformation may be more genetically complex than previously believed. Exhaustive phenotypic characterization, even larger datasets, and collaborative efforts are needed to detect the combination of rare variants conferring risk which, along with specific environmental factors, could be causing the development of this disease.

Medico-legal perspectives on sudden cardiac death in young athletes.

Sudden cardiac death (SCD) in a young athlete represents a dramatic event, and an increasing number of medico-legal cases have addressed this topic. In addition to representing an ethical and medico-legal responsibility, prevention of SCD is directly correlated with accurate eligibility/disqualification decisions, with an inappropriate pronouncement in either direction potentially leading to legal controversy. This review summarizes the common causes of SCD in young athletes, divided into structural (hypertrophic cardiomyopathy, arrhythmogenic cardiomyopathy, congenital coronary artery anomalies, etc.), electrical (Brugada, congenital LQT, Wolf-Parkinson-White syndrome, etc.), and acquired cardiac abnormalities (myocarditis, etc.). In addition, the roles of hereditary cardiac anomalies in SCD in athletes and the effects of a positive result on them and their families are discussed. The medico-legal relevance of pre-participation screening is analyzed, and recommendations from the American Heart Association and European Society of Cardiology are compared. Finally, the main issues concerning the differentiation between physiologic cardiac adaptation in athletes and pathologic findings and, thereby, definition of the so-called gray zone, which is based on exact knowledge of the mechanism of cardiac remodeling including structural or functional adaptions, will be addressed.

Postmortem genetic testing should be recommended in sudden cardiac death cases due to thoracic aortic dissection.

BACKGROUND: Acute thoracic aortic dissections and ruptures, the main life-threatening complications of the corresponding aneurysms, are an important cause of sudden cardiac death. Despite the usefulness of the molecular diagnosis of these conditions in the clinical setting, the corresponding forensic field remains largely unexplored. The main goal of this study was to explore and validate a new massive parallel sequencing candidate gene​ assay as a diagnostic tool for acute thoracic aortic dissection autopsy cases. MATERIALS AND METHODS: Massive parallel sequencing of 22 thoracic aortic disease candidate genes performed in 17 cases of thoracic aortic dissection using AmpliSeq and Ion Proton technologies. Genetic variants were filtered by location, type, and frequency at the Exome Aggregation Consortium and an internal database and further classified based on the American College of Medical Genetics and Genomics (ACMG) recommendations published in 2015. All prioritized results were confirmed by traditional sequencing. RESULTS: From the total of 10 potentially pathogenic genetic variants identified in 7 out of the 17 initial samples, 2 of them were further classified as pathogenic, 2 as likely pathogenic, 1 as possibly benign, and the remaining 5 as variants of uncertain significance, reaching a molecular autopsy yield of 23%, approximately. CONCLUSIONS: This massive parallel sequencing candidate gene approach proved useful for the molecular autopsy of aortic dissection sudden cardiac death cases and should therefore be progressively incorporated into the forensic field, being especially beneficial for the anticipated diagnosis and risk stratification of any other family member at risk of developing the same condition.

PRKG1 and genetic diagnosis of early-onset thoracic aortic disease.

BACKGROUND: The 20% of thoracic aortic aneurysms and dissections independent from the main connective tissue syndromes and expected to be familial has gained importance over the past years. The more frequent pattern of inheritance of these nonsyndromic cases is autosomal dominant with incomplete penetrance and variable expression. Although many candidate genes exist, unresolved familial cases suggest still unravelled genetic variation. The main purpose of this study was to establish the genetic diagnosis of one of those. MATERIALS AND METHODS: To begin with, we applied a candidate gene approach based on both traditional and a customized massive parallel sequencing panel, followed by Illumina HiSeq 2000 whole exome sequencing of four family members affected by early-onset thoracic aortic disease and two unaffected relatives. We prioritized whole exome sequencing results based on variant location, type and frequency in general population databases and performed segregation analysis in 14 family members using traditional sequencing. RESULTS: After the negative results we obtained with candidate gene approaches, the analysis and prioritization of whole exome sequencing results brought out the heterozygote c.530G>A:p.Arg177Gln PRKG1 variant (NM_001098512), located in one of the aortic smooth muscle cell contractile apparatus genes. This candidate variant segregated with thoracic aortic disease, as it was present in seven affected and absent in five unaffected family members, further supporting its causality. CONCLUSIONS: This was the second time PRKG1 was associated with thoracic aortic disease, highlighting and reaffirming it as a strong candidate for gene-based diagnosis of nonsyndromic early-onset cases.

Association between SNPs of Metalloproteinases and Prostaglandin F2α Receptor Genes and Latanoprost Response in Open-Angle Glaucoma.

PURPOSE: To determine whether single nucleotide polymorphisms (SNPs) of genes coding for matrix metalloproteinases (MMPs) and the prostaglandin F2α receptor gene (PTGFR) are related to a response to latanoprost in a white Spanish population of glaucomatous patients. DESIGN: Case-control study. PARTICIPANTS: One hundred twenty-four patients with open-angle glaucoma. METHODS: Genotyping was performed in 117 patients with primary open-angle glaucoma with a minimum treatment duration of 4 weeks. Candidate genes and individual polymorphisms were selected according to the effect on the mechanism of action of latanoprost. Multi-SNP haplotype analyses for associations also were tested. MAIN OUTCOME MEASURES: Diurnal intraocular pressure reduction and genotyping of the SNPs in the MMPs and PTGFR. RESULTS: The PTGFR SNPs were associated with positive (rs6686438, rs10786455) and negative (rs3753380, rs6672484, rs11578155) responses to latanoprost. Multiple testing found 2 genes, PTGFR and MMP-1, were related to refractoriness to latanoprost. CONCLUSIONS: The SNPs of the PTGFR and MMP-1 genes may determine the latanoprost response in a white European Spanish population. This study identified 5 SNPs related to the latanoprost response; 1 SNP, rs3753380, already has been associated with a poor response to latanoprost in a healthy Japanese population. Latanoprost is a commonly used antiglaucomatous drug, and increased knowledge of its mechanism of action will lead to advances in pharmacogenetics.

Involvement of LCA5 in Leber congenital amaurosis and retinitis pigmentosa in the Spanish population.

OBJECTIVE: We aimed to identify novel genetic defects in the LCA5 gene underlying Leber congenital amaurosis (LCA) in the Spanish population and to describe the associated phenotype. DESIGN: Case series. PARTICIPANTS: A cohort of 217 unrelated Spanish families affected by autosomal recessive or isolated retinal dystrophy, that is, 79 families with LCA and 138 families with early-onset retinitis pigmentosa (EORP). A total of 100 healthy, unrelated Spanish individuals were screened as controls. METHODS: High-resolution homozygosity mapping was performed in 44 patients with LCA using genome-wide single nucleotide polymorphism (SNP) microarrays. Direct sequencing of the LCA5 gene was performed in 5 patients who showed homozygous regions at chromosome 6 and in 173 unrelated individuals with LCA or EORP. The ophthalmic history of 8 patients carrying LCA5 mutations was reviewed and additional examinations were performed, including electroretinography (ERG), optical coherence tomography (OCT), and fundus photography. MAIN OUTCOME MEASURES: Single nucleotide polymorphism genotyping, identity-by-descent (IBD) regions, LCA5 mutations, best-corrected visual acuity, visual field assessments, fundus appearance, ERG, and OCT findings. RESULTS: Four novel and 2 previously reported LCA5 mutations have been identified in 6 unrelated families with LCA by homozygosity mapping or Sanger sequencing. Thus, LCA5 mutations have a frequency of 7.6% in the Spanish population. However, no LCA5 mutations were found in 138 patients with EORP. Although most of the identified LCA5 mutations led to a truncated protein, a likely pathogenic missense variant was identified for the first time as a cause of LCA, segregating in 2 families. We also have characterized a novel splicing site mutation at the RNA level, demonstrating that the mutant LCA5 transcript was absent in a patient. All patients carrying LCA5 mutations presented nystagmus, night blindness, and progressive loss of visual acuity and visual field leading to blindness toward the third decade of life. Fundoscopy showed fundus features of pigmentary retinopathy with atrophic macular lesions. CONCLUSIONS: This work reveals a higher frequency of LCA5 mutations in a Spanish LCA cohort than in other populations. This study established gene-specific frequencies and the underlying phenotype of LCA5 mutations in the Spanish population.

Next generation sequencing challenges in the analysis of cardiac sudden death due to arrhythmogenic disorders.

Inherited arrhythmogenic disorders is a relatively common cause of cardiac sudden death in young people. Diagnosis has been difficult so far due to the genetic heterogeneity of the disease. Next generation sequencing (NGS) is offering a new scenario for diagnosis. The purpose of our study was to validate NGS for the analysis of twenty-eight genes known to be associated with inherited arrhythmogenic disorders and therefore with sudden cardiac death. SureSelect hybridization was used to enrich DNA from 53 samples, prior to be sequenced with the SOLID™ System of Life Technologies. Depth of coverage, consistency of coverage across samples, and location of variants identified were assessed. All the samples showed a depth of coverage over 200×, except one of them discarded because of its coverage below 30×. Average percentage of target bp covered at least 20× was 96.45%. In the remaining samples, following a prioritization process 46 possible variants in 31 samples were found, of which 45 were confirmed by Sanger sequencing. After filtering variants according to their minor allele frequency in the Exome Sequencing Project 27 putative pathogenic variants in 20 samples remained. With the use of in silico tools, 13 variants in 11 samples were classified as likely pathogenic. In conclusion, NGS allowed us to accurately detect arrhythmogenic disease causing mutations in a fast and cost-efficient manner that is suitable for daily clinical and forensic practice of genetic testing of this type of disorders.

Penetrance of Dilated Cardiomyopathy in Genotype-Positive Relatives.

BACKGROUND: Disease penetrance in genotype-positive (G+) relatives of families with dilated cardiomyopathy (DCM) and the characteristics associated with DCM onset in these individuals are unknown. OBJECTIVES: This study sought to determine the penetrance of new DCM diagnosis in G+ relatives and to identify factors associated with DCM development. METHODS: The authors evaluated 779 G+ patients (age 35.8 ± 17.3 years; 459 [59%] females; 367 [47%] with variants in TTN) without DCM followed at 25 Spanish centers. RESULTS: After a median follow-up of 37.1 months (Q1-Q3: 16.3-63.8 months), 85 individuals (10.9%) developed DCM (incidence rate of 2.9 per 100 person-years; 95% CI: 2.3-3.5 per 100 person-years). DCM penetrance and age at DCM onset was different according to underlying gene group (log-rank P = 0.015 and P <0.01, respectively). In a multivariable model excluding CMR parameters, independent predictors of DCM development were: older age (HR per 1-year increase: 1.02; 95% CI: 1.0-1.04), an abnormal electrocardiogram (HR: 2.13; 95% CI: 1.38-3.29); presence of variants in motor sarcomeric genes (HR: 1.92; 95% CI: 1.05-3.50); lower left ventricular ejection fraction (HR per 1% increase: 0.86; 95% CI: 0.82-0.90) and larger left ventricular end-diastolic diameter (HR per 1-mm increase: 1.10; 95% CI: 1.06-1.13). Multivariable analysis in individuals with cardiac magnetic resonance and late gadolinium enhancement assessment (n = 360, 45%) identified late gadolinium enhancement as an additional independent predictor of DCM development (HR: 2.52; 95% CI: 1.43-4.45). CONCLUSIONS: Following a first negative screening, approximately 11% of G+ relatives developed DCM during a median follow-up of 3 years. Older age, an abnormal electrocardiogram, lower left ventricular ejection fraction, increased left ventricular end-diastolic diameter, motor sarcomeric genetic variants, and late gadolinium enhancement are associated with a higher risk of developing DCM.

Molecular autopsy: Twenty years of post-mortem diagnosis in sudden cardiac death.

In the forensic medicine field, molecular autopsy is the post-mortem genetic analysis performed to attempt to unravel the cause of decease in cases remaining unexplained after a comprehensive forensic autopsy. This negative autopsy, classified as negative or non-conclusive, usually occurs in young population. In these cases, in which the cause of death is unascertained after a thorough autopsy, an underlying inherited arrhythmogenic syndrome is the main suspected cause of death. Next-generation sequencing allows a rapid and cost-effectives genetic analysis, identifying a rare variant classified as potentially pathogenic in up to 25% of sudden death cases in young population. The first symptom of an inherited arrhythmogenic disease may be a malignant arrhythmia, and even sudden death. Early identification of a pathogenic genetic alteration associated with an inherited arrhythmogenic syndrome may help to adopt preventive personalized measures to reduce risk of malignant arrhythmias and sudden death in the victim's relatives, at risk despite being asymptomatic. The current main challenge is a proper genetic interpretation of variants identified and useful clinical translation. The implications of this personalized translational medicine are multifaceted, requiring the dedication of a specialized team, including forensic scientists, pathologists, cardiologists, pediatric cardiologists, and geneticists.

Detection of the Copy Number Variants of Genes in Patients with Familial Cardiac Diseases by Massively Parallel Sequencing.

INTRODUCTION: The implication of copy number variations in familial heart disease is known, although in-depth knowledge is lacking; hence, more studies are needed to further our understanding. Massively parallel sequencing, thanks to its recent surge in use, is emerging as a valid tool for the detection of this type of variant, through the use of appropriate software. METHODS: We conducted a study with 182 patients diagnosed with mendelian cardiovascular diseases who underwent sequencing using a cardiac gene panel and then a specific calling process for copy number variations (CNVs) with ExomeDepth software, which provides us with a Bayes factor (BF), a score of the probability that a CNV detected is true. RESULTS: After a rigorous CNV prioritization process, we confirmed the variants obtained by MLPA or SNP-based array, finding three real CNVs in five individuals in the MYH11, FBN1 and PDMI7 genes. CONCLUSION: The confirmed CNVs present in all cases BF values > 60, thus establishing a threshold to consider real CNVs in the calling process carried out by ExomeDepth on our gene panel.

Late gadolinium enhancement distribution patterns in non-ischaemic dilated cardiomyopathy: genotype-phenotype correlation.

AIMS: Late gadolinium enhancement (LGE) is frequently found in patients with dilated cardiomyopathy (DCM); there is little information about its frequency and distribution pattern according to the underlying genetic substrate. We sought to describe LGE patterns according to genotypes and to analyse the risk of major ventricular arrhythmias (MVA) according to patterns. METHODS AND RESULTS: Cardiac magnetic resonance findings and LGE distribution according to genetics were performed in a cohort of 600 DCM patients followed at 20 Spanish centres. After exclusion of individuals with multiple causative gene variants or with variants in infrequent DCM-causing genes, 577 patients (34% females, mean age 53.5 years, left ventricular ejection fraction 36.9 ± 13.9%) conformed to the final cohort. A causative genetic variant was identified in 219 (38%) patients, and 147 (25.5%) had LGE. Significant differences were found comparing LGE patterns between genes (P < 0.001). LGE was absent or rare in patients with variants in TNNT2, RBM20, and MYH7 (0, 5, and 20%, respectively). Patients with variants in DMD, DSP, and FLNC showed a predominance of LGE subepicardial patterns (50, 41, and 18%, respectively), whereas patients with variants in TTN, BAG3, LMNA, and MYBPC3 showed unspecific LGE patterns. The genetic yield differed according to LGE patterns. Patients with subepicardial, lineal midwall, transmural, and right ventricular insertion points or with combinations of LGE patterns showed an increased risk of MVA compared with patients without LGE. CONCLUSION: LGE patterns in DCM have a specific distribution according to the affected gene. Certain LGE patterns are associated with an increased risk of MVA and with an increased yield of genetic testing.

Searching for genetic modulators of the phenotypic heterogeneity in Brugada syndrome.

In Brugada syndrome, even within the same family where all affected individuals share the same mutation, phenotypic variation is prominent, with variable penetrance and expressivity, presenting different degrees of involvement. It is difficult to establish a direct correlation between genotype and phenotype to predict prognosis in complications and risk of sudden death. The factors that modulate this inter- and intra-familial phenotypic variability remain to be determined. With the intention of testing whether other genetic factors, in addition to the causal mutation in SCN5A, may have a modulating effect on the Brugada phenotype and the risk of sudden death, we have studied 8 families with a causal variant in SCN5A with at least two affected individuals, one of whom has suffered cardiac arrest or sudden death. Whole exome sequencing was performed looking for additional variants that modify the phenotype and allow us to predict a better or worse prognosis for the evolution of the disease. The results did not show any clear genetic modifier; nevertheless, highlight the possible implication of the cholesterol and fibrosis pathways, as well as the circadian rhythm, as possible modulators of Brugada syndrome phenotype.

The genetic legacy of religious diversity and intolerance: paternal lineages of Christians, Jews, and Muslims in the Iberian Peninsula.

Most studies of European genetic diversity have focused on large-scale variation and interpretations based on events in prehistory, but migrations and invasions in historical times could also have had profound effects on the genetic landscape. The Iberian Peninsula provides a suitable region for examination of the demographic impact of such recent events, because its complex recent history has involved the long-term residence of two very different populations with distinct geographical origins and their own particular cultural and religious characteristics-North African Muslims and Sephardic Jews. To address this issue, we analyzed Y chromosome haplotypes, which provide the necessary phylogeographic resolution, in 1140 males from the Iberian Peninsula and Balearic Islands. Admixture analysis based on binary and Y-STR haplotypes indicates a high mean proportion of ancestry from North African (10.6%) and Sephardic Jewish (19.8%) sources. Despite alternative possible sources for lineages ascribed a Sephardic Jewish origin, these proportions attest to a high level of religious conversion (whether voluntary or enforced), driven by historical episodes of social and religious intolerance, that ultimately led to the integration of descendants. In agreement with the historical record, analysis of haplotype sharing and diversity within specific haplogroups suggests that the Sephardic Jewish component is the more ancient. The geographical distribution of North African ancestry in the peninsula does not reflect the initial colonization and subsequent withdrawal and is likely to result from later enforced population movement-more marked in some regions than in others-plus the effects of genetic drift.

Prevalence of HCM and long QT syndrome mutations in young sudden cardiac death-related cases.

Cardiomyopathies and channelopathies are major causes of sudden cardiac death. The genetic study of these diseases is difficult because of their heterogenic nature not only in their genetic traits but also in their phenotypic expression. The purpose of the present study is the analysis of a wide spectrum of previously known genetic mutations in key genes related to hypertrophic cardiomyopathy (HCM), long QT syndrome (LQTS), and Brugada syndrome (BrS) development. The samples studied include cases of sudden cardiac death (SCD) in young adults and their relatives in order to identify the real impact of genetic screening of SCD in forensic cases. Genetic screening of described variation in 16 genes implicated in the development of HCM and three more genes implicated in LQTS and BrS was performed by using MassARRAY technology. In addition, direct sequencing of the two most prevalent genes implicated in the development of SQTL type 1 and 2 was also carried out. Genetic screening allowed us to unmask four possibly pathogenic mutation carriers in the 49 SCD cases considered; carriers of mutation represent 9% (2/23) of the probands with structural anomalies found after autopsy and 7% (1/14) of the probands with structurally normal hearts after in depth autopsy protocol. One mutation was found among 12 of the recovered SCD cases considered. In people with direct family history of sudden cardiac death, but not themselves, 11 additional mutation carriers were found. Three different mutations were found in six of the 19 LQTS patients, representing three families and two different mutations were found among six patients with previous syncope. Genetic analysis in sudden cardiac death cases could help to elucidate the cause of death, but it also can help in the prevention of future deaths in families at risk. The study presented here shows the importance and relevance of genetic screening in patients with signs of cardiac hypertrophy and in family cases with more than one relative affected.

Association of variants in MYH7, MYBPC3 and TNNT2 with sudden cardiac death-related risk factors in Brazilian patients with hypertrophic cardiomyopathy.

Hypertrophic cardiomyopathy (HCM) is characterized by unexplained left ventricular hypertrophy (LVH) and is one of the major causes of sudden cardiac death (SCD). An exon-targeted gene sequencing strategy was used to investigate the association of functional variants in sarcomeric genes (MYBPC3, MYH7 and TNNT2) with severe LVH and other SCD-related risk factors in Brazilian HCM patients. Clinical data of 55 HCM patients attending a Cardiology Hospital (Sao Paulo city, Brazil) were recorded. Severe LVH, aborted SCD, family history of SCD, syncope, non-sustained ventricular tachycardia and abnormal blood pressure in response to exercise were evaluated as SCD risk factors. Blood samples were obtained for genomic DNA extraction and the exons and untranslated regions of the MYH7, MYBPC3 and TNNT2 were sequenced using Nextera® and MiSEq® reagents. Variants were identified and annotated using in silico tools, and further classified as pathogenic or benign according to the American College of Medical Genetics and Genomics guidelines. Variants with functional effects were identified in MYBPC3 (n = 9), MYH7 (n = 6) and TNNT2 (n = 4). The benign variants MYBPC3 p.Val158Met and TNNT2 p.Lys263Arg were associated with severe LVH (p < 0.05), and the MYH7 p.Val320Met (pathogenic) was associated with family history of SCD (p = 0.037). Increased risk for severe LVH was found in carriers of MYBPC3 Met158 (c.472 A allele, OR = 13.5, 95% CI = 1.80-101.12, p = 0.011) or combined variants (MYBPC3, MYH7 and TNNT2: OR = 12.39, 95% CI = 2.14-60.39, p = 0.004). Carriers of TNNT2 p.Lys263Arg and combined variants had higher values of septum thickness than non-carriers (p < 0.05). Molecular modeling analysis showed that MYBPC3 158Met reduces the interaction of cardiac myosin-binding protein C (cMyBP-C) RASK domain (amino acids Arg215-Ala216-Ser217-Lys218) with tropomyosin. In conclusion, the variants MYBPC3 p.Val158Met, TNNT2 p.Lys263Arg and MYH7 p.Val320Met individually or combined contribute to the risk of sudden cardiac death and other outcomes of hypertrophic cardiomyopathy.

Association of Genetic Variants With Outcomes in Patients With Nonischemic Dilated Cardiomyopathy.

BACKGROUND: The clinical relevance of genetic variants in nonischemic dilated cardiomyopathy (DCM) is unsettled. OBJECTIVES: The study sought to assess the prognostic impact of disease-causing genetic variants in DCM. METHODS: Baseline and longitudinal clinical data from 1,005 genotyped DCM probands were retrospectively collected at 20 centers. A total of 372 (37%) patients had pathogenic or likely pathogenic variants (genotype positive) and 633 (63%) were genotype negative. The primary endpoint was a composite of major adverse cardiovascular events. Secondary endpoints were end-stage heart failure (ESHF), malignant ventricular arrhythmia (MVA), and left ventricular reverse remodeling (LVRR). RESULTS: After a median follow-up of 4.04 years (interquartile range: 1.70-7.50 years), the primary endpoint had occurred in 118 (31.7%) patients in the genotype-positive group and in 125 (19.8%) patients in the genotype-negative group (hazard ratio [HR]: 1.51; 95% confidence interval [CI]: 1.17-1.94; P = 0.001). ESHF occurred in 60 (16.1%) genotype-positive patients and in 55 (8.7%) genotype-negative patients (HR: 1.67; 95% CI: 1.16-2.41; P = 0.006). MVA occurred in 73 (19.6%) genotype-positive patients and in 77 (12.2%) genotype-negative patients (HR: 1.50; 95% CI: 1.09-2.07; P = 0.013). LVRR occurred in 39.6% in the genotype-positive group and in 46.2% in the genotype-negative group (P = 0.047). Among individuals with baseline left ventricular ejection fraction ≤35%, genotype-positive patients exhibited more major adverse cardiovascular events, ESHF, and MVA than their genotype-negative peers (all P < 0.02). LVRR and clinical outcomes varied depending on the underlying affected gene. CONCLUSIONS: In this study, DCM patients with pathogenic or likely pathogenic variants had worse prognosis than genotype-negative individuals. Clinical course differed depending on the underlying affected gene.

A strong genetic association between the tumor necrosis factor locus and proliferative vitreoretinopathy: the retina 4 project.

OBJECTIVE: To assess the genetic contribution to proliferative vitreoretinopathy (PVR) and report the strong association observed in the tumor necrosis factor (TNF) locus. DESIGN: As a component of The Retina 4 Project, a case-controlled, candidate gene association study in the TNF locus was conducted. PARTICIPANTS AND CONTROLS: Blood from 450 patients with (138 cases) and without (312 controls) post-rhegmatogenous retinal detachment (RD) PVR was genotyped to determine polymorphisms located in the TNFα gene. METHODS: Single nucleotide polymorphisms (SNPs) with correlation coefficients of ≥ 0.8 and a minor allelic frequency of ≥ 10% were studied. Functional SNPs or SNPs previously described in association with other inflammatory diseases were also added for analysis. The SNPlex Genotyping System (Applied Biosystems, Foster City, CA) was used for genotyping. Single nucleotide polymorphism and haplotype analyses were performed. Bioinformatic tools were used to evaluate those SNPs that were significantly associated. MAIN OUTCOME MEASURES: Single and haplotypic significant associations with PVR. RESULTS: A total of 11 common tag SNPs in the following genes were analyzed: lymphotoxin alpha (LTA), TNFα, leukocyte-specific transcript 1 (LST1), and the activating natural killer receptor p30 (NCR3). After permutation, there was a significant association in the non-synonymous polymorphism rs2229094(T→C) in the LTA gene (P = 0.0283), which encodes a cysteine to arginine change in the signal peptide. This marker was also present in all significant haplotypic associations and was not observed in any nonsignificant associations. When this SNP was analyzed using bioinformatic tools, the hydropathy profile changed, as well as the transmembrane region and the splicing site predictions. CONCLUSIONS: The strong association found in the rs2229094(T→C) of the LTA gene may indicate an important role of this polymorphism in the development of PVR. If supported in extended studies, the rs2229094(T→C) may have significant implications regarding the genetic risk of the retinal repairing process.

A new approach to long QT syndrome mutation detection by Sequenom MassARRAY system.

Congenital long QT syndrome is an inherited cardiac disorder characterized by a prolonged QT interval and polymorphic ventricular arrhythmias that could result in recurrent syncope, seizures or sudden death as the most dramatic event. Until now QT interval mutations have been described in 12 genes, where the majority of mutations reside in three genes KCNQ1, KCNH2, and SCN5A. Diagnosis and prognosis are directly related with the gene and mutation involved. We have developed a diagnostic approach for long QT syndrome and Brugada syndrome based on published mutations and Sequenom MassArray system. Three diagnostic tests have been developed, oriented to each of the three most prevalent genes in the long QT syndrome. A total of 433 mutations are analyzed in 38 multiplex reactions, allowing their detection in about 48 h. Tests were validated on 502 samples from individuals with different clinical conditions and family history. The average call rates obtained for each of the tests were 93, 83, and 73% in KCNQ1, KCNH2, and SCNA, respectively. Sequenom MassARRAY mutation detection is a reliable, highly flexible, and cost-efficient alternative to conventional methods for genetic testing in long QT syndrome and Brugada syndrome, facilitating flexible upgrades of the version of the test presented here with the inclusion of new mutations.