Percorrer por autor "Laranjeira, Mateus"
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- Doenças mitocondriais na era da sequenciação de nova geração: estudo de 450 doentesPublication . Nogueira, Célia; Pereira, Cristina; Silva, Lisbeth; Laranjeira, Mateus; Lopes, Altina; Neiva, Raquel; Rodrigues, Esmeralda; Campos, Teresa; Martins, Esmeralda; Bandeira, Anabela; Coelho, Margarida; Magalhães, Marina; Damásio, Joana; Gaspar, Ana; Janeiro, Patrícia; Gomes, Levy; Ferreira, Ana Cristina; Jacinto, Sandra; Vieira, José Pedro; Diogo, Luísa; Santos, Helena; Mendonça, Carla; Vilarinho, LauraAs doenças mitocondriais (DM) são doenças raras, clínica e geneticamente heterogéneas, de difícil diagnóstico, para as quais não existe uma terapia eficaz. O desenvolvimento da tecnologia de sequenciação de nova geração (NGS) revolucionou o diagnóstico molecular deste grupo de doenças, permitindo a identificação de novos genes associados a estas patologias. Nesta nova era genética, através da utilização da tecnologia de NGS, estudamos um grupo de 450 doentes suspeitos de DM, sem etiologia molecular. A nossa estratégia combinada de NGS, englobou a sequenciação de um painel de 213 genes nucleares associados a DM e do DNA mitocondrial completo. Neste estudo, identificamos variantes causais em 134 (30%) doentes analisados, 88 dos quais apresentaram variantes no DNA nuclear e 46 no DNA mitocondrial, tratando-se na maioria de doentes pediátricos (66%). Neste grupo de doentes, identificamos 72 variantes patogénicas descritas na literatura e 20 novas variantes provavelmente patogénicas, assim como 62 variantes de significado indeterminado. Como laboratório nacional de referência para o estudo e investigação das DM, demonstramos o contributo da tecnologia de NGS para esclarecer a etiologia molecular destes doentes, para expandir o espectro mutacional associado a estas patologias e oferecer um diagnóstico pré-natal e aconselhamento genético aos casais em risco.
- Functional Characterization of ACAD9 Variants of Uncertain Significance Using a Zebrafish Morpholino Knockdown ModelPublication . Laranjeira, Mateus; Oliveira, Jorge; Santorelli, Filippo; Marchese, Maria; Nogueira, CéliaBackground: ACAD9 is a mitochondrial protein involved in fatty acid β-oxidation and complex I assembly. Mutations in ACAD9 are associated with mitochondrial diseases (MD) of variable severity. Zebrafish (Danio rerio), with conserved mitochondrial physiology and genetic similarity to humans, is a valuable model for assessing the functional impact of variants of uncertain significance (VUS) in MD-related genes.
- Morpholino Knockdown in Zebrafish: A Tool to Investigate the Functional Impact of Variants of Unknown Significance in Mitochondrial DiseasesPublication . Laranjeira, Mateus; Oliveira, Jorge Miguel; Santorelli, Filippo Maria; Marchese, Maria; Nogueira, CéliaMitochondrial diseases (MDs) are heterogeneous multisystemic disorders often caused by genetic defects in either nuclear or mitochondrial DNA. Although next-generation sequencing technologies have dramatically expanded the number of variants associated with these diseases, many remain variants of unknown significance (VUS). This review explores the utility of zebrafish (Danio rerio) as a vertebrate model system for studying mitochondrial dysfunction, with a focused analysis on the application of morpholino oligonucleotides (MOs) to functionally characterize and interpret VUS. MO-induced knockdown produces a transient suppression of target genes during zebrafish early development, recapitulating key MD phenotypes. Furthermore, rescue experiments involving co-injection of MO and either wild-type or mutant mRNA have proven useful to functionally assess the pathogenicity of specific variants. Specifically, while wild-type mRNA rescues the morphant phenotype, failure of mutant mRNA to do so confirms the variant’s pathogenic effect. This approach has successfully linked previously uncharacterized genes to MD and helped reclassify ambiguous variants. The use of MO-based strategies in zebrafish remains a valuable tool for variant interpretation and functional validation, bridging the gap between genomic data and clinical action, and ultimately reducing the diagnostic odyssey. Overall, this review places MO knockdown and rescue assays in zebrafish as a robust and versatile platform to address functional genomics in MD research.
- New Zebrafish Models for Mitochondrial DiseasesPublication . Nogueira, Célia; Laranjeira, Mateus; Pinho, Brígida; Marchese, Maria; Pereira, Cristina; Azevedo, L.; Oliveira, J.; Santorelli, Filippo; Vilarinho, LauraIntroduction: Mitochondrial diseases (MD) are rare disorders with clinical and genetic heterogeneity and no effective therapies. Next Generation Sequencing has advanced MD diagnosis, although the interpretation of variants of unknown significance (VUS) remains a challenge (1). Functional validation is crucial for determining VUS pathogenicity, and zebrafish has emerged as a valuable organism to model MD, due to its conserved physiology and genetic similarity to humans. This project aims to functionally characterize four previously identified VUS in ACAD9 and TSFM using zebrafish as an in vivo model.