👤 Vinicius Nahime Brito

Hypertrophic cardiomyopathy (HCM) is caused by mutations in sarcomere-related genes, with MYBPC3 being the most common. Documenting potential genotype-phenotype associations may allow for more personalized genetic counselling. Observational case-control, cohort, and cross-sectional studies reporting genotype-phenotype associations and the occurrence of predefined events were selected from Cochrane and Medline databases. A random- effects meta-analysis was conducted. Twenty-four studies were included, with 3869 patients enrolled. The mean age at diagnosis of HCM associated with mutations in the MYBPC3 gene was 39.8 years (95 % CI 32.96 to 46.55), and the mean maximum left ventricular thickness was 20.4 mm (95 % CI 19.72 to 21.06). Proportion rates were 12.6 % (95 % CI 5.7 to 21.5 %) for septal reduction therapy, 20.4 % (95 % CI 11.9 to 30.2 %) for the development of heart failure New York Heart Association (NYHA) III/IV functional class, 16.1 % (95 % CI 10.3 to 22.6 %) for the occurrence of atrial fibrillation, and 26 % (95 % CI 17.0 to 36.1 %) for ventricular tachycardia. Cardioverter-defibrillators were implanted in 31.4 % (95 % CI 18.6 to 45.6 %) for secondary prevention, and sudden cardiac arrest occurred in 14.7 % (95 % CI 7.8 to 23.0 %) of patients. Cardiovascular death occurred in 8.6 % of patients over a median of 73 months of follow-up. This is the largest meta-analysis of MYBPC3 HCM patients to date. We were able to obtain data on the proportion rates of events in this population, which allows to answer some questions about the clinical course of HCM disease associated with mutations in the MYBPC3 gene more clearly. We found not only a late disease onset and low mortality risk, but importantly, a non-negligible risk of developing severe heart failure throughout life. Show less

Understanding the immunopathogenesis of COVID-19 has yielded valuable insights into predicting adverse outcomes-particularly mortality. However, significant gaps persist in our comprehension of the complex interplay among the proposed pathophysiological mechanisms. Here, we aim to investigate the immunological factors associated with mortality in critically ill, unvaccinated COVID-19 patients admitted to the intensive care unit (ICU). We conducted a single-center, prospective study involving 56 unvaccinated COVID-19 patients admitted to the ICU. Plasma cytokine levels at admission were quantified using enzyme-linked immunosorbent assay (ELISA). Continuous variables were presented as median (IQR), and categorical variables as frequencies and percentages. Non-parametric tests assessed group differences. Logistic regression and receiver operating characteristic (ROC) curve analyses identified predictors of mortality, with bootstrapping (1000 re-samplings; 95 % BCa CI) applied for model validation. Deceased patients exhibited significantly higher levels of interleukin (IL)-1β, IL-2, IL-6, transforming growth factor (TGF)-β, and interferon (IFN)-γ compared to survivors. Conversely, IL-10 and IL-27 were associated with favorable outcomes. Logistic regression modeling identified elevated IL-2 and IFN-γ levels as significant predictors of mortality. Notably, individual ROC curve analyses demonstrated that IL-1β and TGF-β had excellent discriminatory ability for mortality, while IFN-γ, IL-2, and IL-27 showed very good to excellent discriminatory capacity. Our results indicate that distinct cytokine profiles differentiate survivors from non-survivors in critically ill, unvaccinated COVID-19 patients. These findings highlight the importance of cytokine dysregulation in severe COVID-19 cases and suggest potential targets for prognostic approaches. Further research is warranted to validate these results and translate them into effective clinical management strategies. Show less

The length of ewe productive life (LPL), defined as the number of days between the first and last lambing, is a key indicator of ewe longevity and is directly related to the sustainability of the sheep industry. Therefore, the primary objective of this study was to investigate systematic effects influencing LPL in Katahdin sheep. The LPL of 10,474 Katahdin ewes (69.5% with uncensored and 30.5% with right-censored observations) born between 1992 and 2021 in 58 flocks located across the United States were analyzed. The Kaplan-Meier (K-M) and Cox proportional hazard (Cox PH) methods were used to estimate survival probability. Four Cox PH models were evaluated. Model 1 included contemporary group (CG; flock-year-season of ewe birth) as a random effect and the ewe's dam's age (EDA), ewe's own birth-rearing type (BR; 1/1, 2/1, 2/2, 3/2, 3/3, with the digit-3 including lamb counts ≥ 3), and age at first lambing (AFL) as fixed effects. Models 2 to 4 were an extension of model 1. Model 2 also included average lamb birth weight (ABW) per ewe lifetime, while model 3 included average lamb weaning weight (AWW) per ewe lifetime. Both ABW and AWW were fitted as fixed effects. Model 4 fitted all previous effects together. The factors CG, BR, ABW, and AWW affected LPL (P < 0.05) in all models in which these effects were fitted. The EDA effect only influenced LPL (P < 0.05) in model 1, while AFL had no effect (P > 0.05) in any model. The median LPL ranged from approximately 2 to 3 yr, depending on the risk factors analyzed. In general, Katahdin ewes themselves born in multiple litters, and that produced lambs weighing approximately 5 kg at lambing and 20 to 25 kg at weaning (over their lifespan) had better survival probability. Although the LPL of Katahdin sheep is relatively low, it appears to be a consequence of voluntary culling due to its association with both ABW and AWW. Future studies should quantify the rate of involuntary culling in Katahdin ewes to identify whether longevity indicator traits should be included in more comprehensive breeding objectives. Show less

This study aimed to explore the genetic basis of walking ability and potentially related performance traits in turkey purebred populations. Phenotypic, pedigree, and genomic datasets from 2 turkey lines hatched between 2010 and 2023 were included in the study. Walking ability data, defined based on a scoring system ranging from 1 (worst) to 6 (best), were collected on 192,019 animals of a female line and 235,461 animals of a male line. Genomic information was obtained for 46,427 turkeys (22,302 from a female line and 24,125 from a male line) using a 65K single nucleotide polymorphism (SNP) panel. Variance components and heritability for walking ability were estimated. Furthermore, genetic and phenotypic correlations among walking ability, mortality and disorders, and performance traits were calculated. A genome-wide association study (GWAS) was also conducted to identify SNPs associated with walking ability. Walking ability is moderately heritable (0.23 ± 0.01) in both turkey lines. The genetic correlations between walking ability and the other evaluated traits ranged from -0.02 to -0.78, with leg defects exhibiting the strongest negative correlation with walking ability. In the female line, 31 SNPs were associated with walking ability and overlapped with 116 genes. These positional genes are linked to 6 gene ontology (GO) terms. Notably, genes such as CSRP2, DDX1, RHBDL1, SEZ6L, and CTSK are involved in growth, development, locomotion, and bone disorders. GO terms, including fibronectin binding (GO:0001968), peptide cross-linking (GO:0018149), and catabolic process (GO:0009057), are directly linked with mobility. In the male line, 66 markers associated with walking ability were identified and overlapped with 281 genes. These genes are linked to 12 GO terms. Genes such as RB1CC1, TNNI1, MSTN, FN1, SIK3, PADI2, ERBB4, B3GNT2, and BACE1 are associated with cell growth, myostatin development, and disorders. GO terms in the male line are predominantly related to lipid metabolism. In conclusion, walking ability is moderately heritable in both populations. Furthermore, walking ability can be enhanced through targeted genetic selection, emphasizing its relevance to both animal welfare and productivity. Show less

Hypertrophic cardiomyopathy (HCM) is frequently caused by mutations in the MYPBC3 gene, which encodes the cardiac myosin-binding protein C (cMyBP-C). Most pathogenic variants in MYPBC3 are either nonsense mutations or result in frameshifts, suggesting that the primary disease mechanism involves reduced functional cMyBP-C protein levels within sarcomeres. However, a subset of MYPBC3 variants are missense mutations, and the molecular mechanisms underlying their pathogenicity remain elusive. Upon in vitro differentiation into cardiomyocytes, induced pluripotent stem cells (iPSCs) derived from HCM patients represent a valuable resource for disease modeling. In this study, we generated two iPSC lines from peripheral blood mononuclear cells (PBMCs) of a female with early onset and severe HCM linked to the MYBPC3: c.772G > A variant. Although this variant was initially classified as a missense mutation, recent studies indicate that it interferes with splicing and results in a frameshift. The generated iPSC lines exhibit a normal karyotype and display hallmark characteristics of pluripotency, including the ability to undergo trilineage differentiation. These novel iPSCs expand the existing repertoire of MYPBC3-mutated cell lines, broadening the spectrum of resources for exploring how diverse mutations induce HCM. They additionally offer a platform to study potential secondary genetic elements contributing to the pronounced disease severity observed in this individual. Show less

Familial hypertrophic cardiomyopathy (HCM) stands as a predominant heart condition, characterised by left ventricle hypertrophy in the absence of any associated loading conditions, with affected individuals having an increased risk of developing heart failure and sudden cardiac death (SCD). Two induced pluripotent stem cell (iPSC) lines were derived from peripheral blood mononuclear cells obtained from two unrelated individuals with previously reported nonsense mutations in the MYBPC3 gene. The first individual is a 48-year-old male (F26) with the MYBPC3 c.1731G > A HCM mutation, whereas the second individual is a 43-year-old female (F82) carrying the MYBPC3 c.2670G > A HCM mutation. The generated iPSCs exhibit appropriate expression of pluripotency markers, trilineage differentiation capacity and a normal karyotype. This resource contributes to gaining deeper insights into the pathophysiological mechanisms that underlie HCM. Show less

Familial hypertrophic cardiomyopathy (HCM) is the most common inherited heart condition. HCM patients show left ventricle hypertrophy without any associated loading conditions, being at risk for heart failure and sudden cardiac death. Two induced pluripotent stem cell (iPSC) lines were generated from peripheral blood mononuclear cells obtained from two unrelated individuals, a 54-year-old male (F81) and a 44-year-old female (F93), both carrying the MYBPC3 c.1484G>A HCM mutation. iPSCs show expression of pluripotency markers, trilineage differentiation capacity and a normal karyotype. This resource enables further assessment of the pathophysiological development of HCM. Show less

As the swine industry continues to explore pork quality traits alongside growth, feed efficiency and carcass leanness traits, it becomes imperative to understand their underlying genetic relationships. Due to this increase in the number of desirable traits, animal breeders must also consider methods to efficiently perform direct genetic changes for each trait and evaluate alternative selection indexes with different sets of phenotypic measurements. Principal component analysis (PCA) and genome-wide association studies (GWAS) can be combined to understand the genetic architecture and biological mechanisms by defining biological types (biotypes) that relate these valuable traits. Therefore, the main objectives of this study were to: (1) estimate genomic-based genetic parameters; (2) define animal biotypes utilizing PCA; and (3) utilize GWAS to link the biotypes to candidate genes and quantitative trait loci (QTL). The phenotypic dataset included 2583 phenotypic records from female Duroc pigs from a terminal sire line. The pedigree file contained 193,764 animals and the genotype file included 21,309 animals with 35,651 single nucleotide polymorphisms (SNPs). Eight principal components (PCs), accounting for a total of 99.7% of the population variation, were defined for three growth, eight conventional carcass, 10 pork quality and 18 novel carcass traits. The eight biotypes defined from the PCs were found to be related to growth rate, maturity, meat quality and body structure, which were then related to candidate genes. Of the 175 candidate genes found, six of them [LDHA (SSC1), PIK3C3 (SSC6), PRKAG3 (SSC15), VRTN (SSC7), DLST (SSC7) and PAPPA (SSC1)] related to four PCs were found to be associated with previously defined QTL, linking the biotypes with biological processes involved with muscle growth, fat deposition, glycogen levels and skeletal development. Further functional analyses helped to make connections between biotypes, relating them through common KEGG pathways and gene ontology (GO) terms. These findings contribute to a better understanding of the genetic relationships between growth, carcass and meat quality traits in Duroc pigs, enabling breeders to better understand the biological mechanisms underlying the phenotypic expression of these traits. Show less

Genetic progress for fertility and reproduction traits in dairy cattle has been limited due to the low heritability of most indicator traits. Moreover, most of the quantitative trait loci (QTL) and candidate genes associated with these traits remain unknown. In this study, we used 5.6 million imputed DNA sequence variants (single nucleotide polymorphisms, SNPs) for genome-wide association studies (GWAS) of 18 fertility and reproduction traits in Holstein cattle. Aiming to identify pleiotropic variants and increase detection power, multiple-trait analyses were performed using a method to efficiently combine the estimated SNP effects of single-trait GWAS based on a chi-square statistic. There were 87, 72, and 84 significant SNPs identified for heifer, cow, and sire traits, respectively, which showed a wide and distinct distribution across the genome, suggesting that they have relatively distinct polygenic nature. The biological functions of immune response and fatty acid metabolism were significantly enriched for the 184 and 124 positional candidate genes identified for heifer and cow traits, respectively. No known biological function was significantly enriched for the 147 positional candidate genes found for sire traits. The most important chromosomes that had three or more significant QTL identified are BTA22 and BTA23 for heifer traits, BTA8 and BTA17 for cow traits, and BTA4, BTA7, BTA17, BTA22, BTA25, and BTA28 for sire traits. Several novel and biologically important positional candidate genes were strongly suggested for heifer (SOD2, WTAP, DLEC1, PFKFB4, TRIM27, HECW1, DNAH17, and ADAM3A), cow (ANXA1, PCSK5, SPESP1, and JMJD1C), and sire (ELMO1, CFAP70, SOX30, DGCR8, SEPTIN14, PAPOLB, JMJD1C, and NELL2) traits. These findings contribute to better understand the underlying biological mechanisms of fertility and reproduction traits measured in heifers, cows, and sires, which may contribute to improve genomic evaluation for these traits in dairy cattle. Show less

Identifying genes or genomic regions influencing carcass-quality traits such as fatness (FTN) is essential to optimize the genetic selection processes in beef cattle. The aim of this study was to identify genomic regions associated with FTN in Nellore cattle as well as to elucidate the metabolic pathways related to the phenotypic expression. Ultrasound-based measurements of FTN were collected in 11 750 animals, with 39 903 animals in the pedigree file. Additionally, 1440 animals were genotyped using the GGP-indicus 35K SNP panel, which contained 33 623 SNPs after quality control. Twenty genes related to FTN were found on 11 chromosomes, explaining 12.96% of the total additive genetic variance. Gene ontology revealed seven genes: NR1L2, PKD2, GSK3β, EXT1, RAD51B, SORCS1 and DPH6, associated with important processes related to FTN. In addition, novel candidate genes (MAATS1, LYPD1, CDK5RAP2, RAD51B, c13H2Oorf96 and TRAPPC11) were detected and could provide further knowledge to uncover genetic regions associated to carcass fatness in beef cattle. Show less

Genome-wide association study (GWAS) is a powerful tool to identify candidate genes and genomic regions underlying key biological mechanisms associated with economically important traits. In this context, the aim of this study was to identify genomic regions and metabolic pathways associated with backfat thickness (BFT) and rump fat thickness (RFT) in Nellore cattle, raised in pasture-based systems. Ultrasound-based measurements of BFT and RFT (adjusted to 18 months of age) were collected in 11,750 animals, with 39,903 animals in the pedigree file. Additionally, 1,440 animals were genotyped using the GGP-indicus 35K SNP chip, containing 33,623 SNPs after the quality control. The single-step GWAS analyses were performed using the BLUPF90 family programs. Candidate genes were identified through the Ensembl database incorporated in the BioMart tool, while PANTHER and REVIGO were used to identify the key metabolic pathways and gene networks. A total of 18 genomic regions located on 10 different chromosomes and harbouring 23 candidate genes were identified for BFT. For RFT, 22 genomic regions were found on 14 chromosomes, with a total of 29 candidate genes identified. The results of the pathway analyses showed important genes for BFT, including TBL1XR1, AHCYL2, SLC4A7, AADAT, VPS53, IDH2 and ETS1, which are involved in lipid metabolism, synthesis of cellular amino acids, transport of solutes, transport between Golgi Complex membranes, cell differentiation and cellular development. The main genes identified for RFT were GSK3β, LRP1B, EXT1, GRB2, SORCS1 and SLMAP, which are involved in metabolic pathways such as glycogen synthesis, lipid transport and homeostasis, polysaccharide and carbohydrate metabolism. Polymorphisms located in these candidate genes can be incorporated in commercial genotyping platforms to improve the accuracy of imputation and genomic evaluations for carcass fatness. In addition to uncovering biological mechanisms associated with carcass quality, the key gene pathways identified can also be incorporated in biology-driven genomic prediction methods. Show less

Understanding heat stress physiology and identifying reliable biomarkers are paramount for developing effective management and mitigation strategies. However, little is known about the molecular mechanisms underlying thermal tolerance in animals. In an experimental model of Sprague-Dawley rats subjected to temperatures of 22 ± 1°C (control group; CT) and 42°C for 30 min (H30), 60 min (H60), and 120 min (H120), RNA-sequencing (RNA-Seq) assays were performed for blood (CT and H120), liver (CT, H30, H60, and H120), and adrenal glands (CT, H30, H60, and H120). A total of 53, 1,310, and 1,501 differentially expressed genes (DEGs) were significantly identified in the blood ( Show less

Lactation persistency and milk production are among the most economically important traits in the dairy industry. In this study, we explored the association of over 6.1 million imputed whole-genome sequence variants with lactation persistency (LP), milk yield (MILK), fat yield (FAT), fat percentage (FAT%), protein yield (PROT), and protein percentage (PROT%) in North American Holstein cattle. We identified 49, 3991, 2607, 4459, 805, and 5519 SNPs significantly associated with LP, MILK, FAT, FAT%, PROT, and PROT%, respectively. Various known associations were confirmed while several novel candidate genes were also revealed, including Show less

Patients with tall stature often remain undiagnosed after clinical investigation and few studies have genetically assessed this group, most of them without a systematic approach. To assess prospectively a group of individuals with tall stature, with and without syndromic features, and to establish a molecular diagnosis for their growth disorder. Screening by karyotype (n = 42), chromosome microarray analyses (CMA) (n = 16), MS-MLPA (n = 2) targeted panel (n = 12) and whole-exome sequencing (n = 31). We selected 42 patients with tall stature after exclusion of pathologies in GH/IGF1 axis and divided them into syndromic (n = 30) and non-syndromic (n = 12) subgroups. Frequencies of pathogenic findings. We identified two patients with chromosomal abnormalities including SHOX trisomy by karyotype, one 9q22.3 microdeletion syndrome by CMA, two cases of Beckwith-Wiedemann syndrome by targeted MS-MLPA analysis and nine cases with heterozygous pathogenic or likely pathogenic genetic variants by multigene analysis techniques (FBN1 = 3, NSD1 = 2, NFIX = 1, SUZ12 = 1, CHD8 = 1, MC4R = 1). Three of 20 patients analyzed by WES had their diagnosis established. Only one non-syndromic patient had a definitive diagnosis. The sequential genetic assessment diagnosed 14 out of 42 (33.3%) tall patients. A systematic molecular approach of patients with tall stature was able to identify the etiology in 13 out of 30 (43.3%) syndromic and 1 out of 12 (8.3%) non-syndromic patients, contributing to the genetic counseling and avoiding unfavorable outcomes in the syndromic subgroup. Show less

Milking speed (MS) and temperament (MT) are 2 workability traits of great importance in dairy cattle production and breeding. This is mainly due to an increased intensification of the worldwide production systems and greater adoption of precision technologies with less human-cattle interaction. Both MS and MT are heritable traits and thus, genomic selection is a promising tool to expedite their genetic progress. However, the genetic architecture and biological mechanisms underlying the phenotypic expression of these traits remain underexplored. In this study, we investigated the association of >5.7 million imputed whole-genome sequence variants with MT and MS in 4,381 and 4,219 North American Holstein cattle, respectively. The statistical analyses were performed using a mixed linear model fitting a polygenic effect. We detected 40 and 35 significant SNPs independently associated with MT and MS, respectively, which were distributed across 26 chromosomes. Eight candidate genes (GRIN3A, KCNJ3, BOSTAUV1R417, BOSTAUV1R419, MAP2K5, KCTD3, GAP43, and LSAMP) were suggested to play an important role in MT as they are involved in biologically relevant pathways, such as glutamatergic synapse, vomeronasal receptor and oxytocin signaling. Within their coding and upstream sequences, we used an independent data set to further detect or validate significantly differentiated SNP between cattle breeds with known differences in MT. There were fewer candidate genes potentially implicated in MS, but immunity-related genes (e.g., BOLA-NC1 and LOC512672), also identified in other populations, were validated in this study. The significant SNP and novel candidate genes identified contribute to a better understanding of the biological mechanisms underlying both traits in dairy cattle. This information will also be useful for the optimization of prediction of genomic breeding values by giving greater weights to SNP located in the genomic regions identified. Show less

We present an ancillary study of the Portuguese Registry of Hypertrophic Cardiomyopathy (PRo-HCM). This is one of the largest HCM genetic studies based on a registry. Collected genetic variants were re-analysed for pathogenicity. Demographic, clinical, imaging and outcome data were analysed for associations with genotype, focusing on comparisons between patients with (G+) vs without (G-) a pathogenic/likely pathogenic (P/LP) variant in one the 9 main causal sarcomeric genes. From the 1042 patients in the registry, 528 (51%) had genetic testing. 152 (28%) were G+ and 98 pts. (19%) had variants of unknown significance. From the patients with the 9 mentioned genes sequenced (424 pts), 14.6% had P/LP variants in MYBPC3, 8.7% MYH7, 4.5% TNNT2, 1.7% TNNI3. Patients were 51 ± 16 years-old, 59% males. Genotype was associated with the following: birthplace (p = 0.005); age (p < 0.001); family history of HCM (p < 0.0005); hypertension (p < 0.0005); chest pain (p = 0.015); pattern of hypertrophy (p = 0.006); left ventricular hypertrophy on the ECG (p < 0.0005); family history of sudden cardiac death (SCD) (p = 0.002). G+ patients more frequently had more than one risk factor for SCD (p = 0.002) and a higher ESC-SCD risk score (p = 0.003). In survival analysis, G+ was associated with SCD (p = 0.017) and MYH7+ with LV systolic dysfunction (p = 0.038). Half of the registry patients had genetic testing. Sarcomere-positive patients had distinct demographics, ECG, imaging characteristics and family history and are at increased risk of SCD. The presence of a MYH7 mutation was associated with evolution towards LV systolic dysfunction. Show less

High throughput sequencing technologies have revolutionized the identification of mutations responsible for genetic diseases such as hypertrophic cardiomyopathy (HCM). However, approximately 50% of individuals with a clinical diagnosis of HCM have no causal mutation identified. This may be due to the presence of pathogenic mutations located deep within the introns, which are not detected by conventional sequencing analysis restricted to exons and exon-intron boundaries. The aim of this study was to develop a whole-gene sequencing strategy to prioritize deep intronic variants that may play a role in HCM pathogenesis. The full genomic DNA sequence of 26 genes previously associated with HCM was analysed in 16 unrelated patients. We identified likely pathogenic deep intronic variants in VCL, PRKAG2 and TTN genes. These variants, which are predicted to act through disruption of either splicing or transcription factor binding sites, are 3-fold more frequent in our cohort of probands than in normal European populations. Moreover, we found a patient that is compound heterozygous for a splice site mutation in MYBPC3 and the deep intronic VCL variant. Analysis of family members revealed that carriers of the MYBPC3 mutation alone do not manifest the disease, while family members that are compound heterozygous are clinically affected. This study provides a framework for scrutinizing variation along the complete intronic sequence of HCM-associated genes and prioritizing candidates for mechanistic and functional analysis. Our data suggest that deep intronic variation contributes to HCM phenotype. Show less

Sarcomeric hypertrophic cardiomyopathy has heterogeneous phenotypic expressions, of which sudden cardiac death is the most feared. A genetic diagnosis is essential to identify subjects at risk in each family. The spectrum of disease-causing mutations in the Portuguese population is unknown. Seventy-seven unrelated probands with hypertrophic cardiomyopathy were systematically screened for mutations by PCR and sequencing of five sarcomeric genes: MYBPC3, MYH7, TNNT2, TNNI3 and MYL2. Familial cosegregation analysis was performed in most patients. Thirty-four different mutations were identified in 41 (53%) index patients, 71% with familial hypertrophic cardiomyopathy. The most frequently involved gene was MYBPC3 (66%) with 22 different mutations (8 novel) in 27 patients, followed by MYH7 (22%), TNNT2 (12%) and TNNI3 (2.6%). In three patients (7%), two mutations were found in MYBPC3 and/or MYH7. Additionally, 276 relatives were screened, leading to the identification of a mean of three other affected relatives for each pedigree with the familial form of the disease. Disease-associated mutations were identified mostly in familial hypertrophic cardiomyopathy, corroborating the idea that rarely studied genes may be implicated in sporadic forms. Private mutations are the rule, MYBPC3 being the most commonly involved gene. Mutations in MYBPC3 and MYH7 accounted for most cases of sarcomere-related disease. Multiple mutations in these genes may occur, which highlights the importance of screening both. The detection of novel mutations strongly suggests that all coding regions should be systematically screened. Genotyping in hypertrophic cardiomyopathy enables a more precise diagnosis of the disease, with implications for risk stratification and genetic counseling. Show less

Hypertrophic Cardiomyopathy (HCM) is a complex myocardial disorder with a recognized genetic heterogeneity. The elevated number of genes and mutations involved in HCM limits a gene-based diagnosis that should be considered of most importance for basic research and clinical medicine. In this report, we evaluated High Resolution Melting (HRM) robustness, regarding HCM genetic testing, by means of analyzing 28 HCM-associated genes, including the most frequent 4 HCM-associated sarcomere genes, as well as 24 genes with lower reported HCM-phenotype association. We analyzed 80 Portuguese individuals with clinical phenotype of HCM allowing simultaneously a better characterization of this disease in the Portuguese population. HRM technology allowed us to identify 60 mutated alleles in 72 HCM patients: 49 missense mutations, 3 nonsense mutations, one 1-bp deletion, one 5-bp deletion, one in frame 3-bp deletion, one insertion/deletion, 3 splice mutations, one 5'UTR mutation in MYH7, MYBPC3, TNNT2, TNNI3, CSRP3, MYH6 and MYL2 genes. Significantly 22 are novel gene mutations. HRM was proven to be a technique with high sensitivity and a low false positive ratio allowing a rapid, innovative and low cost genotyping of HCM. In a short return, HRM as a gene scanning technique could be a cost-effective gene-based diagnosis for an accurate HCM genetic diagnosis and hopefully providing new insights into genotype/phenotype correlations. Show less

Apolipoprotein A5 (APOA5) and apolipoprotein E (APOE) play important roles in the metabolism of cholesterol and triglycerides. The aim of this study was to determine the allelic and genotypic distributions of the APOA5-1131T>C (rs 662799) and the APOE HhaI polymorphisms and to identify the association of both individual and combined APOA5-APOE genetic variants and the risk for dyslipidemia in children and adolescents. We genotyped 53 dyslipidemic and 77 normolipidemic individuals. The total cholesterol, triglycerides and HDL cholesterol were determined enzymatically. For APOA5 polymorphism, the presence of the allele C confers an individual risk for dyslipidemia (OR = 2.38, 95% CI = 1.15-4.89; P = 0.018). No significant differences were observed for lipid parameters among the APOA5 groups, except for a higher value of HDLc (P = 0.024) in C-carriers. The allelic and genotypic frequencies of APOE polymorphism were similar between groups and did not increase the susceptibility for dyslipidemia. None of the combined APOA5-APOE polymorphisms increased risk for dyslipidemia. We demonstrated an association between APOA5-1131T>C polymorphism and dyslipidemia in children and adolescents. This finding may be useful to guide new studies with genetic markers down a path toward a better characterization of the genetic risk factors for dyslipidemia and atherosclerotic diseases. Show less

Hypertrophic cardiomyopathy (HCM), a complex myocardial disorder with an autosomal dominant genetic pattern and prevalence of 1:500, is the most frequent cause of sudden death in apparently healthy young people. The benefits of gene-based diagnosis of HCME for both basic research and clinical medicine are limited by the considerable costs of current genetic testing due to the large number of genes and mutations involved in this pathology. However, coupling two high-throughput techniques--mass spectrometry genotyping (MSG) and high resolution melting (HRM)--is an encouraging new strategy for HCM diagnosis. Our aim was to evaluate the diagnostic efficacy of both techniques in this pathology by studying 13 individuals with a clinical phenotype of HCM. Peripheral blood samples were collected from: (i) seven subjects with a clinical diagnosis of HCM, all bearing known mutations previously identified by dideoxy sequencing and thus being used as blinded samples (sample type 1); (ii) one individual with a clinical diagnosis of HCM negative for mutations after dideoxy sequencing of the five most common HCM genes, MYH7, MYBPC3, TNNI3, TNNT2 and MYL2 (sample type 2); and (iii) five individuals individual with a clinical diagnosis of HCM who had not previously been genetically studied (sample type 3). The 13 samples were analyzed by MSG for 534 known mutations in 32 genes associated with HCM phenotypes and for all coding regions and exon-intron boundaries of the same HCM genes by HRM. The 32 studied genes include the most frequent HCM-associated sarcomere genes, as well as 27 genes with lower reported HCM phenotype association. This coupled genotyping strategy enabled us to identify a c.128delC (p.A43Vfs165) frame-shift mutation in the CSRP3 gene, a gene not usually studied in current HCM genetics. The heterozygous CSRP3 mutation was found in two patients (sample types 2 and 3) aged 50 and 52 years, respectively, both with diffuse left ventricular hypertrophy. Furthermore, this coupled strategy enabled us to find a novel mutation, c.817C >T (p.Arg273Cys), in MYBPC3 in an individual from sample type 3, subsequently confirmed by dideoxy sequencing. This novel mutation in MYBPC3, not present in 200 chromosomes from 200 healthy individuals, affects a codon known to harbor an HCM-causing mutation--p.Arg253His. In conclusion, in the cohort used in this work coupling two technologies, MSG and HRM, with high sensitivity and low false positive results, enabled rapid, innovative and low-cost genotyping of HCM patients, which may in the short-term be suitable for accurate genetic diagnosis of HCM. Show less

Hypertrophic cardiomyopathy (HCM) is a genetic disease associated with mutations in genes encoding cardiac sarcomere proteins. A mutation is identified in two-thirds of cases, and more frequently in familial forms. Doubts remain concerning the true identity of the sporadic form. To compare, in a genotyped population, the phenotypic expression of the disease over time in patients with familial and sporadic HCM. 79 patients with HCM, aged 39 +/- 17.8 years at diagnosis, were followed for 12 +/- 9.5 (1-30) years and divided into two groups: G1 (familial)--68 patients (24 unrelated index patients, 44 relatives), follow-up time (FUP) 12 +/- 9.8 (1-30) years; G2 (sporadic)1 index patients (no phenotypic disease in first-degree relatives), FUP 10.8 +/- 8 (2-24) years. Fabry disease was excluded in G2. The two groups were compared regarding clinical, ECG and echocardiographic (echo) features at diagnosis and after FUP. Five sarcomere genes (MYH7, MYBPC3, TNNT2, MYL2 and TNNI3) were screened for mutations by direct sequencing, after PCR amplification with intronic sets of oligonucleotide primers designed according to the published genomic sequence of the genes. A) Thirteen different mutations (in 3 genes) were identified in 14 index patients in G1; only in one patient in G2 was a mutation found. B) The two groups differed clinically in age at diagnosis (G1: 37.18 (4-79) years; G2: 51 +/- 14 (19-67) years; p = 0.02), and family history of sudden cardiac death (G1: 12/24 families; G2: 1/11 families; p = 0.04). Age, gender, FUP, symptoms, need for medical treatment, cardiovascular (CV) hospitalization and mortality (CV or any cause) were similar. C) ECG patterns did not differ, although significant (but similar) changes occurred in 45% (G1) and 36% (G2) of patients (p = 0.75). These changes were in the same direction, with a trend in both groups toward the development of atrial fibrillation and/or advanced conduction disease. D) Echo features (only considered in adults) were similar despite significant changes during FUP (in 68% of G1, and 82% of G2; p = 0.48). These changes also followed the same tendency: progression to a more diffuse pattern of ventricular hypertrophy (G1: 52%; G2: 73%; p = 0.33) and development of left atrial dilatation (G1: 37%; G2: 45%; p = 0.52). The similar phenotypic expression and behavior over time in familial and sporadic forms of HCM strongly indicate that the disease is one and the same. Differences in genetic findings, age at diagnosis and family history of sudden death suggest that sporadic forms may be caused by low penetrance de novo mutations in sarcomeric genes other than those associated with familial disease. Show less