Introduction: Dilated cardiomyopathy (DCM) is a disease of the heart muscle characterized by ventricular dilatation and impaired systolic function. Familial forms account for 30-50% of cases. Autosomal dominant inheritance is the predominant pattern of transmission. Causal genetic variants have been identified in several genes and molecular diagnosis has implications for genetic counseling and risk stratification. Objective: We aimed to estimate the frequency of genetic variants and the molecular basis of DCM in Portugal. Methods: We performed a multicenter study of unrelated patients, recruited between 2013 and 2014. Variants in 15 genes were screened using PCR with direct sequencing (next-generation sequencing with at least 30-fold coverage combined with Sanger sequencing). Results: A total of 107 patients were included, 64 (60%) men, mean age at diagnosis 38±13 years, with 48 (45%) familial cases. In total, 31 rare variants in eight genes (mainly in MYBPC3, TNNT2 and LMNA) were identified, in 28 patients (26%). Only four variants had been previously described in association with DCM, 11 with hypertrophic cardiomyopathy, and nine variants were novel. Four variants were likely pathogenic and the remainder were of uncertain significance. We found no major differences in the main clinical and imaging characteristics between patients with or without rare variants and patients with likely pathogenic variants. Conclusions: Our results reflect the complexity and diversity of DCM genetics. For better interpretation of the pathogenicity of the variants found and their causative roles in DCM, molecular cascade screening of families is imperative. Further insight into genotype-phenotype correlations and risk stratification is desirable. Resumo: Introdução: A miocardiopatia dilatada (MCD) é uma doença do músculo cardíaco caracterizada por dilatação ventricular e compromisso da função sistólica. As formas familiares são responsáveis por 30 a 50% dos casos. O padrão de hereditariedade predominante é o autossómico dominante. Variantes genéticas causais foram identificadas em vários genes e o diagnóstico molecular tem implicações para o aconselhamento genético e estratificação de risco. Objetivo: Avaliar a base molecular da MCD em Portugal. Métodos: Estudo multicêntrico de doentes não relacionados, recrutados entre 2013 e 2014. Foram analisados 15 genes, através da técnica de PCR com sequenciação direta (NGS com pelo menos uma cobertura de 30 vezes combinada com sequenciação de Sanger). Resultados: Foram incluídos 107 pacientes, 64 (60%) homens, idade média ao diagnóstico de 38 ± 13 anos, com 48 (45%) casos familiares. Foram identificadas 31 variantes raras, em oito genes, (principalmente MYBPC3, TNNT2 e LMNA) em 28 pacientes (26%). Apenas quatro variantes tinham sido previamente descritas em associação com MCD, 11 com miocardiopatia hipertrófica e nove variantes eram novas. Quatro variantes foram classificadas como provavelmente patogénicas e as restantes de significado incerto. Não encontrámos diferenças significativas nas principais características clínicas e imagiológicas entre doentes com ou sem variantes raras e doentes com variantes provavelmente patogénicas. Conclusões: Estes resultados refletem a complexidade e diversidade genética da MCD. Para uma melhor interpretação da patogenicidade das variantes e potencial causalidade, o rastreio molecular das famílias é imperativo. Uma visão mais aprofundada das correlações genótipo-fenótipo e da estratificação de risco é desejável. Keywords: Dilated cardiomyopathy, Genetic variant, Next-generation sequencing, Palavras-chave: Miocardiopatia dilatada, Variante genética, Sequenciação massiva paralela

The association of genetic polymorphisms with low bone mineral density in elite athletes have not been considered previously. The present study found that bone mass phenotypes in elite and pre-elite dancers are related to genetic variants at the Wnt/β-catenin and ER pathways.

Background: In several cancer models, it was shown that tumor mutation load correlates with response to immune checkpoint blockade therapy. However, whole exome sequencing of FFPE samples is not ideal for implementation on molecular pathology laboratories. In colorectal cancer (CRC), mutation load is correlated with microsatellite instability (MSI), which can therefore be used as surrogate marker for mutation load. In this study, we aimed at determining whether a target NGS-based mutation panel can be used for routine testing of mutation load in cancer, by assessing its performance in identifying MSI+ and MSI- CRC samples.

ulcerative colitis (UC) is a chronic inflammatory disorder of the gastrointestinal tract. The great heterogeneity that characterises this disease leads to the urgent need of a molecular biomarker able to stratify UC patients according to their disease severity and therapeutic needs. We have previously shown that UC patients exhibit a deficiency of a specific sugar chain (branched N-glycans) on intestinal T cells due to a significant reduction of the transcription of MGAT5 glycogene. This alteration was associated with mucosal T-cell hyperactivation and disease severity. Herein, we have evaluated whether MGAT5 genetic variants (SNPs) that were previously associated with increased susceptibility to other autoimmune diseases, can be associated with UC severity and response to therapy. Three SNPs of the intronic region of MGAT5 were genotyped in 929 UC patients from two European cohorts, Portugal and Belgium, using TaqMan SNP genotyping assays. Single SNP and haplotype associations were determined for UC clinical characteristics with the “SNPasssoc” and “haplo.stats” packages in R, and their functional effect was evaluated measuring the impact of MGAT5 genetic variants on the MGAT5 mRNA levels in peripheral blood T cells from UC patients. All 3 SNPs and a specific haplotype (GGT) were associated with non-response to immunosuppressors (SNP1–A carrier (OR = 2.21; p = 0.032); SNP2–G carrier (OR = 3.11; p = 0.004); SNP3–T carrier (OR = 2.29; p = 0.030); GGT (OR = 2.83; p = 0.007)) and with bad disease course (patients with more than 5 years of diagnosis that needed step-up to biologics; SNP2–GG genotype (OR = 3.55; p = 0.003); SNP3–TT genotype (OR = 3.03; p = 0.004); GGT (OR = 2.24; p = 0.007)). The same GGT haplotype but in Belgian cohort was further associated with severe disease course (need of biologics in the first 2 years after diagnosis—OR = 2.11; p = 0.037; SNP2–G carrier (OR = 2.21; p = 0.027) and SNP3–T carrier (OR = 2.51; p = 0.012)), as well as with disease extension (OR = 7.75; p = 0.007; G (SNP2) and T (SNP3) carriers—OR = 2.17; p = 0.041 and OR = 2.81; p = 0.007, respectively). In addition, the haplotype ACA appeared to be associated with family history (OR = 2.39; p = 0.021; SNP1 AA genotype—OR=3.59;p = 0.021) in Belgian cohort. Interestingly, HIGH-risk MGAT5 genotypes were associated with low levels of MGAT5 gene expression on blood T cells. Altogether, we show that genetic variants in the MGAT5 glycogene may be used to stratify HIGH vs. LOW risk UC patients serving as a potential biomarker that may help the process of therapy-decision-making.

Rheumatoid arthritis (RA) is characterized by increased bone resorption and impaired bone formation. Osteoblast function is regulated by the canonical LRP5/Wnt/β-catenin pathway. Bone mineral density and RA joint destruction are partially inherited. In line with this, we found significant associations between LRP5 SNPs (p.A1330V, p.N740N, p.V667M) and RA radiographic damage severity.

According to existing literature, bone health in ballet dancers is controversial. We have verified that, compared to controls, young female and male vocational ballet dancers have lower bone mineral density (BMD) at both impact and non-impact sites, whereas female professional ballet dancers have lower BMD only at non-impact sites.