Browsing by Author "Quelhas, D"
Now showing 1 - 2 of 2
Results Per Page
Sort Options
- 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.
- 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).