Browsing by Author "Janeiro, P"
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- Congenital Disorders of Glycosylation in Portugal—Two Decades of ExperiencePublication . Quelhas, D; Martins, E; Azevedo, L; Bandeira, A; Diogo, L; Garcia, P; Sequeira, S; Ferreira, AC; Teles, EL; Rodrigues, E; Fortuna, AM; Mendonça, C; Fernandes, HC; Medeira, A; Gaspar, A; Janeiro, P; Oliveira, A; Laranjeira, F; Ribeiro, I; Souche, E; Race, V; Keldermans, L; Matthijs, G; Jaeken, JObjective: To describe the clinical, biochemical, and genetic features of both new and previously reported patients with congenital disorders of glycosylation (CDGs) diagnosed in Portugal over the last 20 years. Study design: The cohort includes patients with an unexplained multisystem or single organ involvement, with or without psychomotor disability. Serum sialotransferrin isoforms and, whenever necessary, apolipoprotein CIII isoforms and glycan structures were analyzed. Additional studies included measurement of phosphomannomutase (PMM) activity and analysis of lipid-linked oligosaccharides in fibroblasts. Sanger sequencing and massive parallel sequencing were used to identify causal variants or the affected gene, respectively. Results: Sixty-three individuals were diagnosed covering 14 distinct CDGs; 43 patients diagnosed postnatally revealed a type 1, 14 a type 2, and 2 a normal pattern on serum transferrin isoelectrofocusing. The latter patients were identified by whole exome sequencing. Nine of them presented also a hypoglycosylation pattern on apolipoprotein CIII isoelectrofocusing, pointing to an associated O-glycosylation defect. Most of the patients (62%) are PMM2-CDG and the remaining carry pathogenic variants in ALG1, ATP6AP1, ATP6AP2, ATP6V0A2, CCDC115, COG1, COG4, DPAGT1, MAN1B1, SLC35A2, SRD5A3, RFT1, or PGM1. Conclusions: Portuguese patients with CDGs are presented in this report, some of them showing unique clinical phenotypes. Among the 14 genes mutated in Portuguese individuals, 8 are shared with a previously reported Spanish cohort. However, regarding the mutational spectrum of PMM2-CDG, the most frequent CDG, a striking similarity between the 2 populations was found, as only 1 mutated allele found in the Portuguese group has not been reported in Spain.
- Phenylketonuria in Portugal: Genotype–Phenotype Correlations Using Molecular, Biochemical, and Haplotypic AnalysesPublication . Ferreira, F; Azevedo, L; Neiva, R; Sousa, C; Fonseca, H; Marcão, A; Rocha, H; Carmona, C; Ramos, S; Bandeira, A; Martins, E; Campos, T; Rodrigues, E; Garcia, P; Diogo, L; Ferreira, AC; Sequeira, S; Silva, F; Rodrigues, L; Gaspar, A; Janeiro, P; Amorim, A; Vilarinho, LBackground: The impairment of the hepatic enzyme phenylalanine hydroxylase (PAH) causes elevation of phenylalanine levels in blood and other body fluids resulting in the most common inborn error of amino acid metabolism (phenylketonuria). Persistently high levels of phenylalanine lead to irreversible damage to the nervous system. Therefore, early diagnosis of the affected individuals is important, as it can prevent clinical manifestations of the disease. Methods: In this report, the biochemical and genetic findings performed in 223 patients diagnosed through the Portuguese Neonatal Screening Program (PNSP) are presented. Results: Overall, the results show that a high overlap exists between different types of variants and phenylalanine levels. Molecular analyses reveal a wide mutational spectrum in our population with a total of 56 previously reported variants, most of them found in compound heterozygosity (74% of the patients). Intragenic polymorphic markers were used to assess the haplotypic structure of mutated chromosomes for the most frequent variants found in homozygosity in our population (p.Ile65Thr, p.Arg158Gln, p.Leu249Phe, p.Arg261Gln, p.Val388Met, and c.1066-11G>A). Conclusion: Our data reveal high heterogeneity at the biochemical and molecular levels and are expected to provide a better understanding of the molecular basis of this disease and to provide clues to elucidate genotype-phenotype correlations.
- Phenylketonuria in Portugal: Genotype-Phenotype Correlations Using Molecular, Biochemical, and Haplotypic AnalysesPublication . Ferreira, F; Azevedo, L; Neiva, R; Sousa, C; Fonseca, H; Marcão, A; Rocha, H; Carmona, C; Ramos, S; Bandeira, A; Martins, E; Campos, T; Rodrigues, E; Garcia, P; Diogo, L; Ferreira, AC; Sequeira, S; Silva, F; Rodrigues, L; Gaspar, A; Janeiro, P; Amorim, A; Vilarinho, LThe impairment of the hepatic enzyme phenylalanine hydroxylase (PAH) causes elevation of phenylalanine levels in blood and other body fluids resulting in the most common inborn error of amino acid metabolism (phenylketonuria). Persistently high levels of phenylalanine lead to irreversible damage to the nervous system. Therefore, early diagnosis of the affected individuals is important, as it can prevent clinical manifestations of the disease.
- Pyruvate Dehydrogenase Complex Deficiency: Updating the Clinical, Metabolic and Mutational Landscapes in a Cohort of Portuguese PatientsPublication . Pavlu-Pereira, H; Silva, MJ; Florindo, C; Sequeira, S; Ferreira, AC; Duarte, S; Rodrigues, AL; Janeiro, P; Oliveira, A; Gomes, D; Bandeira, A; Martins, E; Gomes, R; Soares, S; Tavares de Almeida, I; Vicente, JB; Rivera, IBackground: The pyruvate dehydrogenase complex (PDC) catalyzes the irreversible decarboxylation of pyruvate into acetyl-CoA. PDC deficiency can be caused by alterations in any of the genes encoding its several subunits. The resulting phenotype, though very heterogeneous, mainly affects the central nervous system. The aim of this study is to describe and discuss the clinical, biochemical and genotypic information from thirteen PDC deficient patients, thus seeking to establish possible genotype-phenotype correlations. Results: The mutational spectrum showed that seven patients carry mutations in the PDHA1 gene encoding the E1α subunit, five patients carry mutations in the PDHX gene encoding the E3 binding protein, and the remaining patient carries mutations in the DLD gene encoding the E3 subunit. These data corroborate earlier reports describing PDHA1 mutations as the predominant cause of PDC deficiency but also reveal a notable prevalence of PDHX mutations among Portuguese patients, most of them carrying what seems to be a private mutation (p.R284X). The biochemical analyses revealed high lactate and pyruvate plasma levels whereas the lactate/pyruvate ratio was below 16; enzymatic activities, when compared to control values, indicated to be independent from the genotype and ranged from 8.5% to 30%, the latter being considered a cut-off value for primary PDC deficiency. Concerning the clinical features, all patients displayed psychomotor retardation/developmental delay, the severity of which seems to correlate with the type and localization of the mutation carried by the patient. The therapeutic options essentially include the administration of a ketogenic diet and supplementation with thiamine, although arginine aspartate intake revealed to be beneficial in some patients. Moreover, in silico analysis of the missense mutations present in this PDC deficient population allowed to envisage the molecular mechanism underlying these pathogenic variants. Conclusion: The identification of the disease-causing mutations, together with the functional and structural characterization of the mutant protein variants, allow to obtain an insight on the severity of the clinical phenotype and the selection of the most appropriate therapy.
- Síndrome de Guillain-Barré em Idade Pediátrica. Protocolo de ActuaçãoPublication . Sampaio, MJ; Figueiroa, S; Temudo, T; Gomes, S; Janeiro, P; Silva, RO protocolo de actuação na Síndrome de Guillain-Barré em idade pediátrica foi elaborado com o intuito de rever as mais recentes recomendações internacionais e de traçar linhas orientadoras de actuação. É constituído por duas partes: a primeira é a introdução teórica, resultante da revisão bibliográfica, e a segunda o Protocolo de actuação. Tratando-se de uma patologia para a qual ainda não existe um consenso, sobretudo no que respeita ao tratamento, optou-se por incluir as várias opções de tratamento recomendadas, permitindo a cada Unidade aplicar aquela com a qual possui mais experiência.
- A Síndrome de Smith-Lemli-Opitz: Características Fenotípicas e Genotípicas dos Doentes PortuguesesPublication . Cardoso, ML; Bandeira, A; Lopes, A; Rodrigues, M; Venâncio, M; Sales Marques, J; Janeiro, P; Ferreira, I; Quelhas, D; Sequeira, S; Soares, G; Lourenço, T; Rodrigues, R; Gaspar, A; Nunes, L; Marques, F; Martins, EA síndrome de Smith-Lemli-Opitz (SLOS) é uma síndrome polimalformativa de transmissão autossómica recessiva causada por um défice metabólico da biossíntese do colesterol, que se caracteriza por dismorfias craniofaciais, anomalias congénitas de vários órgãos (salientando-se as do esqueleto e do aparelho urogenital), restrição de crescimento intra-uterino (RCIU), alterações comportamentais e atraso mental. É causada por mutações no gene DHCR7, que codifica para a enzima 7-dehidrocolesterol reductase, responsável pelo último passo da via metabólica da síntese do colesterol. A SLOS caracteriza-se por níveis diminuídos de colesterol e concentrações altas do seu precursor, 7-dehidrocolesterol, no sangue e tecidos. Procedeu-se a uma análise comparativa dos fenótipo e genótipo de quinze casos de SLOS de origem portuguesa, e são tecidas considerações quanto às dificuldades e limitações inerentes ao diagnóstico, e ao facto de esta doença hereditária do metabolismo dever ser considerada no diagnóstico diferencial das situações de (i) hipocolesterolémia, (ii) RCIU e (iii) síndromes polimalformativas,(especialmente quando crianças com atraso de crescimento apresentam simultaneamente sindactilia do segundo e terceiro dedos do pé e microcefalia e/ou narinas antevertidas entre outras anomalias).