Percorrer por autor "Regla Vargas, Carmen"
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- Molecular profile and peripheral markers of neurodegeneration in patients with Niemann-Pick type C: Decrease in Plasminogen Activator Inhibitor type 1 and Platelet-Derived Growth Factor type AAPublication . Hammerschmidt, Tatiane Grazieli; Encarnação, Marisa; Lamberty Faverzani, Jéssica; de Fátima Lopes, Franciele; Oliveira, Fabiano Poswar de; Fischinger Moura de Sousa, Carolina; Ribeiro, Isaura; Alves, Sandra; Giugliani, Roberto; Regla Vargas, CarmenNiemann-Pick type C1 (NPC1) is a fatal inherited disease, caused by pathogenic variants in NPC1 gene, which leads to intracellular accumulation of non-esterified cholesterol and glycosphingolipids. This accumulation leads to a wide range of clinical manifestations, including neurological and cognitive impairment as well as psychiatric disorders. The pathophysiology of cerebral damage involves loss of Purkinje cells, synaptic disturbance, and demyelination. Miglustat, a reversible inhibitor of glucosylceramide synthase, is an approved treatment for NPC1 and can slow neurological damage. The aim of this study was to assess the levels of peripheric neurodegeneration biomarkers of NPC1 patients, namely brain-derived neurotrophic factor (BDNF), platelet-derived growth factors (PDGF-AA and PDGF-AB/BB), neural cell adhesion molecule (NCAM), PAI-1 Total and Cathepsin-D, as well as the levels of cholestane-3β,5α,6β-triol (3β,5α,6β-triol), a biomarker for NPC1. Molecular analysis of the NPC1 patients under study was performed by next generation sequencing (NGS) in cultured fibroblasts. We observed that NPC1 patients treated with miglustat have a significant decrease in PAI-1 total and PDGF-AA concentrations, and no alteration in BDNF, NCAM, PDGF-AB/BB and Cathepsin D. We also found that NPC1 patients treated with miglustat have normalized levels of 3β,5α,6β-triol. The molecular analysis showed four described mutations, and for two patients was not possible to identify the second mutated allele. Our results indicate that the decrease of PAI-1 and PDGF-AA in NPC1 patients could be involved in the pathophysiology of this disease. This is the first work to analyze those plasmatic markers of neurodegenerative processes in NPC1 patients.
- The p.Ala1035Val variant in Niemann–Pick type C1: Clinical and molecular characterization in Brazilian and Portuguese patients suggests a shared founder effectPublication . Alegretti, Ana Paula; Hammerschmidt, Tatiane; Ribeiro, Isaura; Quelhas, Dulce; Polese-Bonato, Márcia; Saraiva-Pereira, Maria Luiza; Martins, Esmeralda; Guigliani, Roberto; Encarnação, Marisa; Alves Sandra; Regla Vargas, CarmenIntroduction: Niemann–Pick disease type C1 (NPC1, OMIM 257220) is a rare, progressive, and fatal autosomal recessive lysosomal storage disorder caused by pathogenic variants in the NPC1 gene. These variants disrupt intracellular lipid trafficking, leading to the accumulation of cholesterol and glycosphingolipids and resulting in severe, multisystem dysfunction for which no cure currently exists. Materials and methods: To investigate the potential founder effect and shared ancestry of the p.Ala1035Val variant, we analyzed 30 genetically confirmed NPC1 cases, comprising 18 Brazilian (12 of whom were homozygous) and 12 Portuguese participants (3 of whom were homozygous), each carrying at least one p.Ala1035Val allele. Diagnosis was established by clinical evaluation, biochemical assays, and filipin staining, with molecular confirmation by NPC1 genotyping. Results: All analyzed individuals exhibited a conserved haplotype across the SNVs in exons 6 (c.644 A > G, p.His215Arg), 12 (c.1926G > C, p.Ile642Met), 17 (c.2572 A > G, p.Ile858Val), and 18 (c.2793C > T, p.Asn931=), strongly supporting a shared founder effect consistent with an Iberian-associated ancestral background. Among Brazilian (n = 14), visceral involvement occurred in 10/14 (71.4%), predominantly hepatosplenomegaly (6/14, 42.9%), and developmental/cognitive alterations in 10/14 (71.4%), followed by ataxia or gait disturbance in 4/14 (28.6%). Among the Portuguese (n = 3), all presented with visceral involvement, characterized by hepatosplenomegaly (3/3, 100%); one had developmental delay (1/3, 33.3%), and none exhibited ataxia/gait disturbance. Despite the small sample size, clinical patterns appeared similar between the two groups, with differences likely reflecting sampling variability. Discussion: These findings expand the known variant spectrum of NPC1 in Brazilian and Portuguese populations, supporting a possible founder effect resulting from Portuguese colonisation. They also highlight the clinical value of haplotype analysis as a tool for tracing disease origin and improving stratification in medical settings. Furthermore, they emphasise the importance of refining early diagnostic strategies to optimise patient management and improve outcomes in NPC, while highlighting the need for larger, multicenter studies to corroborate this hypothesis and refine its clinical and genetic implications.