Identification of pathogenic variants in the brazilian cohort with familial hypercholesterolemia using exon-targeted gene sequencing

Familial hypercholesterolemia (FH) is a monogenic disease characterized by high plasma low-density lipoprotein cholesterol (LDL-c) levels and increased risk of premature atherosclerotic cardiovascular disease. Mutations in FH-related genes account for 40% of FH cases worldwide. In this study, we aimed to assess the pathogenic variants in FH-related genes in the Brazilian FH cohort FHBGEP using exon-targeted gene sequencing (ETGS) strategy. FH patients (n = 210) were enrolled at five clinical sites and peripheral blood samples were obtained for laboratory testing and genomic DNA extraction. ETGS was performed using MiSeq platform (Illumina). To identify deleterious variants in LDLR, APOB, PCSK9, and LDLRAP1, the long-reads were subjected to Burrows-Wheeler Aligner (BWA) for alignment and mapping, followed by variant calling using Genome Analysis Toolkit (GATK) and ANNOVAR for variant annotation. The variants were further filtered using in-house custom scripts and classified according to the American College Medical Genetics and Genomics (ACMG) guidelines. A total of 174 variants were identified including 85 missense, 3 stop-gain, 9 splice-site, 6 InDel, and 71 in regulatory regions (3'UTR and 5'UTR). Fifty-two patients (24.7%) had 30 known pathogenic or likely pathogenic variants in FH-related genes according to the American College Medical and Genetics and Genomics guidelines. Fifty-three known variants were classified as benign, or likely benign and 87 known variants have shown uncertain significance. Four novel variants were discovered and classified as such due to their absence in existing databases. In conclusion, ETGS and in silico prediction studies are useful tools for screening deleterious variants and identification of novel variants in FH-related genes, they also contribute to the molecular diagnosis in the FHBGEP cohort.

Identification of pathogenic variants in the Brazilian cohort with Familial hypercholesterolemia using exon-targeted gene sequencing.

Familial hypercholesterolemia (FH) is a monogenic disease characterized by high plasma low-density lipoprotein cholesterol (LDL-c) levels and increased risk of premature atherosclerotic cardiovascular disease. Mutations in FH-related genes account for 40% of FH cases worldwide. In this study, we aimed to assess the pathogenic variants in FH-related genes in the Brazilian FH cohort FHBGEP using exon-targeted gene sequencing (ETGS) strategy. FH patients (n = 210) were enrolled at five clinical sites and peripheral blood samples were obtained for laboratory testing and genomic DNA extraction. ETGS was performed using MiSeq platform (Illumina). To identify deleterious variants in LDLR, APOB, PCSK9, and LDLRAP1, the long-reads were subjected to Burrows-Wheeler Aligner (BWA) for alignment and mapping, followed by variant calling using Genome Analysis Toolkit (GATK) and ANNOVAR for variant annotation. The variants were further filtered using in-house custom scripts and classified according to the American College Medical Genetics and Genomics (ACMG) guidelines. A total of 174 variants were identified including 85 missense, 3 stop-gain, 9 splice-site, 6 InDel, and 71 in regulatory regions (3'UTR and 5'UTR). Fifty-two patients (24.7%) had 30 known pathogenic or likely pathogenic variants in FH-related genes according to the American College Medical and Genetics and Genomics guidelines. Fifty-three known variants were classified as benign, or likely benign and 87 known variants have shown uncertain significance. Four novel variants were discovered and classified as such due to their absence in existing databases. In conclusion, ETGS and in silico prediction studies are useful tools for screening deleterious variants and identification of novel variants in FH-related genes, they also contribute to the molecular diagnosis in the FHBGEP cohort.

Clinical Features, Genetic Findings, and Risk Stratification in Arrhythmogenic Right Ventricular Cardiomyopathy: Data From a Brazilian Cohort.

BACKGROUND: Arrhythmogenic right ventricular cardiomyopathy (ARVC), a rare inherited disease, causes ventricular tachycardia, sudden cardiac death, and heart failure (HF). We investigated ARVC clinical features, genetic findings, natural history, and the occurrence of life-threatening arrhythmic events (LTAEs), HF death, or heart transplantation (HF-death/HTx) to identify risk factors. METHODS: The clinical course of 111 consecutive patients with definite ARVC, predictors of LTAE, HF-death/HTx, and combined events were analyzed in the entire cohort and in a subgroup of 40 patients without sustained ventricular arrhythmia before diagnosis. RESULTS: The 5-year cumulative probability of LTAE was 30% and HF-death/HTx was 10%. Predictors of HF-death/HTx were reduced right ventricle ejection fraction (HR: 0.93; P=0.010), HF symptoms (HR: 4.37; P=0.010), epsilon wave (HR: 4.99; P=0.015), and number of leads with low QRS voltage (HR: 1.28; P=0.001). Each additional lead with low QRS voltage increased the risk of HF-death/HTx by 28%. Predictors of LTAE were prior syncope (HR: 1.81; P=0.040), number of leads with T wave inversion (HR: 1.17; P=0.039), low QRS voltage (HR: 1.12; P=0.021), younger age (HR: 0.97; P=0.006), and prior ventricular arrhythmia/ventricular fibrillation (HR: 2.45; P=0.012). Each additional lead with low QRS voltage increased the risk of LTAE by 17%. In patients without ventricular arrhythmia before clinical diagnosis of ARVC, the number of leads with low QRS voltage (HR: 1.68; P=0.023) was independently associated with HF-death/HTx. CONCLUSIONS: Our study demonstrated the characteristics of a specific cohort with a high prevalence of arrhythmic burden at presentation, male predominance, younger age and HF severe outcomes. Our main results suggest that the presence and extension of low QRS voltage can be a risk predictor for HF-death/HTx in ARVC patients, regardless of the arrhythmic risk. This study can contribute to the global ARVC risk stratification, adding new insights to the international current scientific knowledge.

Racial inequalities in multimorbidity: baseline of the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil).

BACKGROUND: Evidence of multimorbidity has come mainly from high-income regions, while disparities among racial groups have been less explored. This study examined racial differences in multimorbidity in the multiracial cohort of the Longitudinal Study of Adult Health (Estudo Longitudinal de Saúde do Adulto), ELSA-Brasil. METHODS: The study examined baseline (2008-2010) data for 14 099 ELSA-Brasil participants who self-reported being white, mixed-race, or black. A list of 16 morbidities was used to evaluate multimorbidity, operationalised by simple count into ≥ 2, ≥ 3, ≥ 4, ≥ 5 and ≥ 6 morbidities, in addition to evaluating the number of coexisting conditions. Prevalence ratios (PR) were estimated from logistic models and a quantile model was used to examine racial differences graphically in the distribution quantiles for the number of morbidities. RESULTS: Overall prevalence of multimorbidity (≥ 2 morbidities) was 70% and, after controlling for age and sex, was greater among mixed-race and black participants - by 6% (PR: 1.06; 95% CI: 1.03-1.08) and 9% (PR: 1.09; 95% CI: 1.06-1.12), respectively - than among white participants. As the cutoff value for defining multimorbidity was raised, so the strength of the association increased, especially among blacks: if set at ≥ 6 morbidities, the prevalence was 27% greater for those of mixed-race (PR: 1.27; 95% CI: 1.07-1.50) and 47% greater for blacks (PR: 1.47; 95% CI: 1.22-1.76) than for whites. The disparities were smaller in the lower morbidity distribution quantiles and larger in the upper quantiles, indicating a heavier burden of disease, particularly on blacks. CONCLUSIONS: Multimorbidity was common among adults and older adults in a Brazilian cohort, but important racial inequalities were found. Raising the cutoff point for defining multimorbidity revealed stronger associations between race/skin colour and multimorbidity, indicating a higher prevalence of multimorbidity among mixed-race and black individuals than among whites and that the former groups coexisted more often with more complex health situations (with more coexisting morbidities). Interventions to prevent and manage the condition of multimorbidity that consider the social determinants of health and historically discriminated populations in low- and middle-income regions are necessary.

Kefir metabolites in a fly model for Alzheimer's disease.

Alzheimer's Disease (AD) is the most common cause of dementia among elderly individuals worldwide, leading to a strong motor-cognitive decline and consequent emotional distress and codependence. It is traditionally characterized by amyloidogenic pathway formation of senile plaques, and recent studies indicate that dysbiosis is also an important factor in AD's pathology. To overcome dysbiosis, probiotics-as kefir-have shown to be a great therapeutic alternative for Alzheimer's disease. In this present work, we explored kefir as a probiotic and a metabolite source as a modulator of microbiome and amyloidogenic pathway, using a Drosophila melanogaster model for AD (AD-like flies). Kefir microbiota composition was determined through 16S rRNA sequencing, and the metabolome of each fraction (hexane, dichloromethane, ethyl acetate, and n-butanol) was investigated. After treatment, flies had their survival, climbing ability, and vacuolar lesions accessed. Kefir and fraction treated flies improved their climbing ability survival rate and neurodegeneration index. In conclusion, we show that kefir in natura, as well as its fractions may be promising therapeutic source against AD, modulating amyloidogenic related pathways.

Triglyceride glucose index as a tool to motivate early lifestyle modification in young adults at diabetes risk: The Baependi Heart Study.

Considering that the incidence of type 2 diabetes mellitus (T2DM) has been increasing especially in developing countries and becoming a global public health problem, this study aims to evaluate the association between triglyceride glucose index (TyG) - which is a mathematical product of the fasting blood glucose and triglyceride levels - and incident T2DM in an adult sample in the Baependi Heart Study (BHS). The data were from the BHS cohort consisting of two periods: cycle 1 (2005-2006; n = 1712; 119 families) and cycle 2 (2010-2013; n = 3017; 127 families). A total of 1121 individuals (both sexes, 18-100 years) were selected if they were assessed in both cycles and not diagnosed with T2DM at baseline (cycle 1). Our findings showed that a participant's risk of developing T2DM increased almost 10 times for a one-unit increase in the TyG (odds ratio OR = 10.17, 95% CI, 7.51-13.93). The association when stratified by age was OR = 28.13 [95% CI, 14.03-56.41] for young adults, meaning that the risk of developing T2DM increased more than 28 times for a one-unit increase in the TyG. For the other groups, young middle-aged adults, old middle-aged adults, and seniors, we found OR = 4.84 [95% CI, 2.91-8.06], OR = 28.73 [95% CI, 10.63-77.65, and OR = 9.88 [95% CI, 3.16-30.90], respectively. A higher TyG implies a significant increase in the risk of developing T2DM, which could be an important screening tool to target early lifestyle intervention in Brazil.

Body adiposity index in assessing the risk of type 2 diabetes mellitus development: the Baependi Heart Study.

BACKGROUND: The association between diabetes and obesity is very well established. Faced with this, several anthropometric indices of adiposity are often involved in studies on diabetes. Our main goal in this paper is to evaluate the association between body adiposity index (BAI) and type 2 diabetes mellitus (T2DM) in a sample of the Brazilian population after 5-year follow-up. METHODS: The data used come from the Baependi Heart Study cohort, which consists of two periods: cycle 1 (2005-2006) and cycle 2 (2010-2013). Individuals of both sexes (n = 1121) were selected by excluding participants with type 2 diabetes mellitus at baseline or those that were lost to follow-up. RESULTS: The diabetic subjects showed higher systolic blood pressure, BAI, body mass index, waist circumference and fasting glucose levels. In addition, using mixed-effects logistic regression, we found that the elevation of a single unit of BAI represented an increase of 8.4% in the risk of a patient developing T2DM (OR = 1.084 [95% CI 1.045-1.124]). CONCLUSIONS: Obesity is recognised as one of the most important risk factors for T2DM and BAI has proven to be a useful tool in estimating the risk of a patient developing T2DM in a Brazilian population.

Genetic associations of bradykinin type 2 receptor, alpha-adrenoceptors and endothelial nitric oxide synthase with blood pressure and left ventricular mass in outpatients without overt heart disease.

BACKGROUND: Physiological pathways such as bradykinin, renin-angiotensin, neurohormones and nitric oxide have been shown to play an important role in the regulation of cardiovascular function. Genetic variants of these pathways may impact blood pressure and left ventricular (LV) mass in different populations. To evaluate associations of genetic polymorphisms of bradykinin B2 receptor (BDKRB2), alpha-adrenergic receptors (ADRA) and endothelial nitric oxide synthase (eNOS) on the modulation of the blood pressure and the left ventricular mass. METHODS: We enrolled 758 individuals without overt heart disease. Blood pressure was estimated by auscultatory method during the clinical examination. Left ventricular (LV) mass was assessed by echocardiography. Genotypes for ADRA1A rs1048101, ADRA2A rs553668, ADRA2B rs28365031, eNOS rs2070744, eNOS rs1799983, and BDKRB2 rs5810761 polymorphisms were assessed by high-resolution melting analysis. RESULTS: BDKRB2 polymorphism rs5810761 was associated with blood pressure. Carriers of DD genotype had higher levels of SBP and DBP than carrier of II genotype (p = 0.013 and p = 0.007, respectively). eNOS polymorphism rs1799983 was associated with DBP. Carriers of GT genotype had lower levels of DBP than carriers of GG genotype (p = 0.018). eNOS polymorphism rs2070744 was associated with LV mass. Carriers of TC genotype had higher LV mass than carriers of TT genotype (p = 0.028). CONCLUSIONS: In a cohort of individuals without overt heart disease, the BDKRB2 rs5810761 polymorphism (DD genotype carriers) were associated higher systolic and diastolic blood pressures, and the eNOS rs1799983 polymorphism (T allele carriers) were associated with lower diastolic blood pressure. The eNOS rs2070744 polymorphism (C allele carriers) was associated with higher left ventricular mass. These data suggest that eNOS and bradykinin receptor genetic variants may be potential markers of common cardiovascular phenotypes.

Erosive Tooth Wear and Dietary Patterns: A Clinical Study.

PURPOSE: Evidence exists which suggests that a vegetarian diet is a predisposing factor to erosive tooth wear. The aim of this study was to assess the influence of dietary pattern (vegetarian, lacto-ovo vegetarian and omnivore) on erosive tooth wear. MATERIALS AND METHODS: Two hundred seven subjects (29 vegetarians, 96 lacto-ovo vegetarians and 82 omnivores) underwent an oral assessment and were asked to answer questionnaires about diet and oral care. RESULTS: Individuals who followed vegetarian and lacto-ovo vegetarian diets had statistically significantly more erosive tooth wear than did omnivores (p = 0.004). Conversely, omnivores presented more tooth loss than did lacto-ovo vegetarians (p = 0.027). Being a vegetarian or a lacto-ovo vegetarian entailed an increased risk (4 times and 2.5 times, respectively) of presenting erosive tooth wear than being omnivorous. CONCLUSION: Vegetarian and lacto-ovo vegetarian dietary patterns seem to favour the loss of dental structure by erosion. Vegetarian patients should thus be informed about preventive measures and treated accordingly.

The Duffy null genotype is associated with a lower level of CCL2, leukocytes and neutrophil count but not with the clinical outcome of HTLV-1 infection.

Purpose. Chemokines are important in the immune response against viral infections, and may play a role in human T-lymphotropic virus 1 (HTLV-1)-associated myelopathy/tropical spastic paraparesis (HAM/TSP) pathogenesis. Polymorphisms in the Duffy antigen receptor for chemokines (DARC), such as rs12075 (A>G; FY*B>FY*A) and rs281477 (-46T>C; GATA-1 box) may influence circulating concentrations of proinflammatory chemokines. We investigate whether Duffy genotypes influence the HTLV-1 proviral load (PVL) level, HTLV-1 infection outcome and chemokine concentrations in HTLV-1 asymptomatic carriers (AC=162), HAM/TSP patients (HAM=135) and seronegative individuals (SN=71).Methodology. Quantification of plasmatic IL8, CCL2 and CCL5 were performed by flow cytometry and Duffy genotypes were investigated by real-time PCR. HTLV-1 PVL was quantified in peripheral blood. To control for spurious association, individual ancestry profiles in AC and HAM groups were investigated.Results/Key findings. PVL and IL8 level were significantly higher in the HAM group than in the AC group, but were not associated with Duffy genotypes. The highest CCL2 and CCL5 levels were seen in the SN group, and there was no difference when comparing the infected groups. The level of CCL5 was not associated with Duffy genotypes. The polymorphism -46 C/C that abrogates the DARC expression on the erythrocytes was significantly associated with lower levels of CCL2, neutrophil and white blood cell (WBC) counts in HTLV-1-infected individuals.Conclusion. We conclude that although the Duffy null genotype was associated with leukopenia, neutropenia and lower levels of CCL2, the data do not suggest the influence of Duffy genotypes on the neurologic outcome of HTLV-1 infection, but may be a confounding factor in comparison HTLV-1-infected populations with different ancestries, especially when defining inflammatory biomarkers.

Worse inflammatory profile in omnivores than in vegetarians associates with the gut microbiota composition.

AIMS: To describe the abundance of major phyla and some genera in the gut microbiota of individuals according to dietary habits and examine their associations with inflammatory markers, insulin resistance, and cardiovascular risk profile. METHODS: A total of 268 non-diabetic individuals were stratified into groups of dietary types (strict vegetarians, lacto-ovo-vegetarians, and omnivores). The taxonomic composition and phylogenetic structure of the microbiota were obtained through the analysis of the 16S rRNA gene. Samples were clustered into operational taxonomic units at 97% similarity using GreenGenes 13.5 database. Clinical, biochemical, and circulating inflammatory markers were compared by ANOVA or Kruskal-Wallis test. RESULTS: The sample (54.2% women, mean age 49.5 years) was composed of 66 strict vegetarians, 102 lacto-ovo-vegetarians and 100 omnivores. Considering the entire sample, the greatest abundant phyla were Firmicutes (40.7 ± 15.9%) and Bacteroidetes (39.5 ± 19.9%), and no difference in abundances was found between individuals with normal and excess weight. Stratifying by dietary types, the proportion of Firmicutes was lower and of Bacteroidetes was higher in strict vegetarians when compared to lacto-ovo-vegetarians and omnivores. At the genus level, strict vegetarians had a higher Prevotella abundance and Prevotella/Bacteroides ratio than the other groups. They also had a lower proportion of Faecalibacterium than lacto-ovo-vegetarians, and both vegetarian groups had higher proportions than did omnivores. Succinivibrio and Halomonas from the Proteobacteria phylum were overrepresented in omnivores. The omnivorous group showed higher values of anthropometric data, insulin, HOMA-IR, and a worse lipid profile. Inflammatory markers exhibited a gradual and significant increase from the vegetarians and lacto-ovo-vegetarians to the omnivorous group. CONCLUSIONS: There are differences in gut microbiota composition of individuals with distinct dietary habits, who differ according to their inflammatory and metabolic profiles. Based on the findings relative to bacteria abundances and on their recognized actions in the metabolism, we suggest that exposure to animal foods may favor an intestinal environment which could trigger systemic inflammation and insulin resistance-dependent metabolic disorders.

Increasing The Genetic Admixture of Available Lines of Human Pluripotent Stem Cells.

Human pluripotent stem cells (hPSCs) may significantly improve drug development pipeline, serving as an in vitro system for the identification of novel leads, and for testing drug toxicity. Furthermore, these cells may be used to address the issue of differential drug response, a phenomenon greatly influenced by genetic factors. This application depends on the availability of hPSC lines from populations with diverse ancestries. So far, it has been reported that most lines of hPSCs derived worldwide are of European or East Asian ancestries. We have established 23 lines of hPSCs from Brazilian individuals, and we report the analysis of their genomic ancestry. We show that embryo-derived PSCs are mostly of European descent, while induced PSCs derived from participants of a national-wide Brazilian cohort study present high levels of admixed European, African and Native American genomic ancestry. Additionally, we use high density SNP data and estimate local ancestries, particularly those of CYP genes loci. Such information will be of key importance when interpreting variation among cell lines with respect to cellular phenotypes of interest. The availability of genetically admixed lines of hPSCs will be of relevance when setting up future in vitro studies of drug response.

The contributions of dipeptidyl peptidase IV to inflammation in heart failure.

Circulating dipeptidyl peptidase IV (DPPIV) activity correlates with cardiac dysfunction in humans and experimental heart failure (HF) models. Similarly, inflammatory markers are associated with poorer outcomes in HF patients. However, the contributions of DPPIV to inflammation in HF remain elusive. Therefore, this study aimed to investigate whether the cardioprotective effects of DPPIV inhibition after myocardial injury are accompanied by reduced cardiac inflammation, whether circulating DPPIV activity correlates with the levels of systemic inflammatory markers in HF patients, and whether leukocytes and/or splenocytes may be one of the sources of circulating DPPIV in HF. Experimental HF was induced in male Wistar rats by left ventricular myocardial injury after radiofrequency catheter ablation. The rats were divided into three groups: sham, HF, and HF + DPPIV inhibitor (sitagliptin). Six weeks after surgery, cardiac function, perfusion and inflammatory status were evaluated. Sitagliptin treatment improved cardiac function and perfusion, reduced macrophage infiltration, and diminished the levels of inflammatory biomarkers including TNF-α, IL-1ß, and CCL2. In HF patients, serum DPPIV activity correlated with CCL2, suggesting that leukocytes may be the source of circulating DPPIV in HF. Unexpectedly, DPPIV release was higher in splenocytes from HF rats and similar in HF circulating mononuclear cells compared with those from sham, suggesting an organ-specific modulation of DPPIV in HF. Collectively, our data provide new evidence that the cardioprotective effects of DPPIV inhibition in HF may be due to suppression of inflammatory cytokines. Moreover, they suggest that a vicious circle between DPPIV and inflammation may contribute to HF development and progression.

Nutritional aspects of Noonan syndrome and Noonan-related disorders.

Rasopathies are a group of rare disorders characterized by neurocardiofaciocutaneous involvement, and caused by mutations in several genes of the RAS/MAPK pathway. In the present study, we characterized growth parameters, body composition, and nutritional aspects of children and adults (n = 62) affected by these disorders, mainly Noonan syndrome, using an indirect method-anthropometry-and a 24-hr recall questionnaire. The growth parameters in our cohort showed short stature, especially in individuals with RAF1 and SHOC2 mutations, lower obesity rates compared to the control population, and BMI scores highest in individuals with BRAF mutations and lowest in individuals with SHOC2. Body composition showed a compromise in the upper arm muscle circumference, with a statistically significant difference in the z-score of triceps skinfold (P = 0.0204) and upper arm fat area (P = 0.0388) between BRAF and SHOC2 groups and in the z-score of triceps skinfold between RAF1 and SHOC2 (P = 0.0218). The pattern of macronutrient consumption was similar to the control population. Our study is the first to address body composition in RASopathy individuals and the data indicate a compromise not only in adipose tissue, but also in muscle mass. Studies using different techniques, such as dual-energy X-ray absorptiometry or imaging studies, which give a more precise delineation of fat and non-fat mass, are required to confirm our results, ultimately causing an impact on management strategies. © 2016 Wiley Periodicals, Inc.

Alpha2A-adrenergic receptor and eNOS genetic polymorphisms are associated with exercise muscle vasodilatation in apparently healthy individuals.

PURPOSE: Muscle vasodilatation during exercise has been associated with cardiovascular health and may be influenced by genetic variability. The purpose of this study was to evaluate functional genetic polymorphisms of physiologic pathways related to the regulation of the cardiovascular function (alpha-adrenergic receptors, endothelial nitric oxide synthase and bradykinin B2 receptor) and exercise muscle vasodilatation in apparently healthy men and women. METHODS: We enrolled 689 individuals without established cardiovascular disease that had attended a check-up program. The vasodilatation was studied with venous occlusion plethysmography and determined by the increase of vascular conductance during handgrip exercise. Genotypes for ADRA1A Arg347Cys (rs1048101), ADRA2A 1780 C > T (rs553668), ADRA2B Del 301-303 (rs28365031), eNOS 786 T > C (rs2070744), eNOS Glu298Asp (rs1799983) and BDKRB2 (rs5810761) polymorphisms were assessed by polymerase chain reaction followed by high resolution melting analysis. RESULTS: The eNOS rs2070744 polymorphism was significantly associated with forearm vascular conductance during exercise in women. Women with CC genotype showed higher vasodilatation than carriers of TC and TT genotypes (p = 0.043). The ADRA2A rs553668 polymorphism was significantly associated with forearm vascular conductance during exercise in men. Men with TT genotype had higher vasodilatation than carriers of CT and CC genotypes (p = 0.025). CONCLUSIONS: eNOS rs207074 polymorphism in women and ADRA2A rs553668 polymorphism in men were associated with the increase of forearm vascular conductance during handgrip exercise. These findings suggest that eNOS and ADRA2A genetic polymorphisms may be potential markers of exercise muscle vasodilatation.

Intragenic Deletion in the LIFR Gene in a Long-Term Survivor with Stüve-Wiedemann Syndrome.

Stüve-Wiedemann syndrome (SWS, OMIM 601559) is a rare autosomal recessive bent-bone dysplasia, caused by loss-of-function mutations in the leukemia inhibitory factor receptor (LIFR) gene, which usually leads to early death. Only few patients with long-term survival have been described in the literature. We report on a 5-year-old boy from a consanguineous marriage with molecular analysis for the LIFR gene. Sanger and next-generation sequencing (NGS) of LIFR were performed. Copy number variation analysis with NGS showed a novel mutation as the cause for the syndrome: an intragenic homozygous deletion in LIFR, involving exons 15-20. Bridging PCR was carried out to confirm the intragenic deletion. This is the first description of a large deletion in LIFR, broadening the spectrum of mutations in SWS. Besides the reported allelic heterogeneity, further studies such as exome sequencing are required to identify a novel gene in order to confirm the locus heterogeneity in SWS.

Exercise-induced muscle vasodilatation and treadmill exercise test responses in individuals without overt heart disease.

BACKGROUND: The beneficial effects of exercise on cardiovascular health may be related to the improvement in several physiologic pathways, including peripheral vascular function. The aim of this study was to evaluate the relationship between cardiovascular responses during the treadmill exercise test and exercise-induced muscle vasodilatation in individuals without overt heart disease. METHODS: The study included 796 asymptomatic subjects (431 females and 365 males) without overt heart disease. We evaluated the heart rate (chronotropic reserve and heart rate recovery), blood pressure (maximum systolic and diastolic blood pressure as well as systolic blood pressure recovery) and exercise capacity during symptom-limited treadmill exercise testing. Exercise-induced muscle vasodilatation was studied with venous occlusion plethysmography and estimated by forearm blood flow and vascular conductance responses during a 3-min handgrip maneuver. RESULTS: Forearm blood flow increase during the handgrip exercise was positively associated with heart rate recovery during treadmill exercise testing (p < 0.001). Forearm vascular conductance increase during the handgrip exercise was inversely associated with exercise diastolic blood pressure during exercise treadmill testing (p = 0.038). No significant association was found between exercise capacity and exercise-induced muscle vasodilation. CONCLUSION: In a sample of individuals without overt heart disease, exercise-induced muscle vasodilatation was associated with heart rate and blood pressure responses during treadmill exercise testing, but was not associated with exercise capacity. These findings suggest that favorable hemodynamic and chronotropic responses are associated with better vasodilator capacity, but exercise capacity does not predict muscle vasodilatation.

Different approaches for dealing with rare variants in family-based genetic studies: application of a Genetic Analysis Workshop 17 problem.

Rare variants are becoming the new candidates in the search for genetic variants that predispose individuals to a phenotype of interest. Their low prevalence in a population requires the development of dedicated detection and analytical methods. A family-based approach could greatly enhance their detection and interpretation because rare variants are nearly family specific. In this report, we test several distinct approaches for analyzing the information provided by rare and common variants and how they can be effectively used to pinpoint putative candidate genes for follow-up studies. The analyses were performed on the mini-exome data set provided by Genetic Analysis Workshop 17. Eight approaches were tested, four using the trait's heritability estimates and four using QTDT models. These methods had their sensitivity, specificity, and positive and negative predictive values compared in light of the simulation parameters. Our results highlight important limitations of current methods to deal with rare and common variants, all methods presented a reduced specificity and, consequently, prone to false positive associations. Methods analyzing common variants information showed an enhanced sensibility when compared to rare variants methods. Furthermore, our limited knowledge of the use of biological databases for gene annotations, possibly for use as covariates in regression models, imposes a barrier to further research.