Browsing by Author "Lima, Margarida Reis"
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- Development of NIPBL locus-specific database using LOVD: from novel mutations to further genotype-phenotype correlations in Cornelia de Lange SyndromePublication . Oliveira, Jorge; Dias, Cristina; Redeker, Egbert; Costa, Eurico; Silva, João; Lima, Margarida Reis; Den Dunnen, Johan T.; Santos, RosárioThe establishment of Locus Specific Databases (LSDB) is a crucial aspect for the Human Genetics field and one of the aims of the Human Variation Project. We report the development of a publicly accessible LSDB for the NIPBL gene (http://www.lovd.nl/NIPBL) implicated in Cornelia de Lange Syndrome (CdLS). This rare disorder is characterized by developmental and growth retardation, typical facial features, limb anomalies, and multiple organ involvement. Mutations in the NIPBL gene, the product of which is involved in control of the cohesion complex, account for over half of the patients currently characterized. The NIPBL LSDB adopted the Leiden Open Variation database (LOVD) software platform, which enables the comprehensive Web-based listing and curation of sequence variations and associated phenotypical information. The NIPBL-LOVD database contains 199 unique mutations reported in 246 patients (last accessed April 2010). Information on phenotypic characteristics included in the database enabled further genotype–phenotype correlations, the most evident being the severe form of CdLS associated with premature termination codons in the NIPBL gene. In addition to the NIPBL LSDB, 50 novel mutations are described in detail, resulting from a collaborative multicenter study. Hum Mutat 31:1216–1222, 2010. © 2010 Wiley-Liss, Inc.
- Molecular analysis of the GNPTAB and GNPTG genes in 13 patients with mucolipidosis type II or type III - identification of eight novel mutationsPublication . Encarnação, Marisa; Lacerda, Lúcia; Costa, Roberto; Prata, Maria João; Coutinho, Maria Francisca; Ribeiro, Helena; Lopes, Lurdes; Pineda, M.; Ignatius, J.; Galvez, H.; Mustonen, A.; Vieira, P.; Lima, Margarida Reis; Alves, SandraMucolipidosis II (ML II) and mucolipidosis III (ML III) are diseases in which the activity of the uridine diphosphate (UDP)-N-acetylglucosamine:lysosomal enzyme N-acetylglucosamine-1-phosphotransferase (GlcNAc-phosphotransferase) is absent or reduced, respectively. In the absence of mannose phosphorylation, trafficking of lysosomal hydrolases to the lysosome is impaired. In these diseases, mistargeted lysosomal hydrolases are secreted into the blood, resulting in lysosomal deficiency of many hydrolases and a storage-disease phenotype. GlcNAc-phosphotransferase is a multimeric transmembrane enzyme composed of three subunits (alpha, beta and gamma) encoded by two genes -GNPTAB and GNPTG. Defects in GNPTAB result in ML II and III whereas mutations in GNPTG were only found in ML III patients. We have performed a molecular analysis of the GNPTAB and GNPTG genes in 13 mucolipidosis II and III patients (10 Portuguese, one Finnish, one Spanish of Arab origin and one Indian). Mutations were identified by the study of both cDNA and gDNA. The GNPTAB and GNPTG mRNA expressions were determined by quantitative reverse transcriptase polymerase chain reaction (qRT-PCR). The study led to the identification of 11 different mutations. Eight of these mutations are novel, six in the GNPTAB gene [c.121delG (V41FfsX42), c.440delC (A147AfsX5), c.2249_50insA (N750KfsX8), c.242G>T (W81L), c.1208T>C (I403T) and c.1999G>T (p.E667X)] and two in the GNPTG gene [c.610-1G>T and c.639delT (F213LfsX7)]. With regard to the mRNA expression studies, the values obtained by qRT-PCR indicate the possible existence of feedback regulation mechanisms between alpha/beta and the gamma subunits.
- The use of prealbumin concentration as a biomarker of nutritional status in treated phenylketonuric patientsPublication . Rocha, Júlio César; Almeida, Manuela Ferreira; Carmona, Carla; Cardoso, Maria Luís; Borges, Nuno; Soares, Isabel; Salcedo, Graça; Lima, Margarida Reis; Azevedo, Isabel; Van Spronsen, Francjan J.BACKGROUND/AIMS: The neurological sequelae resulting from untreated phenylketonuria are diminished by the success of early introduced and continued dietary treatment. Nowadays, nutritional status is gaining importance in the follow-up of these patients. The aim of this work was to study the relevance of prealbumin concentration as biomarker of protein nutritional status of phenylketonuric patients. METHODS: We collected data from 69 phenylketonuric patients on food intake, blood prealbumin and blood phenylalanine concentrations. Protein insufficiency was defined as prealbumin z-scores below the 5th percentile of reference population. Additionally, we considered a prealbumin concentration of 20 mg/dl as a threshold level. RESULTS: Nine patients (13%) showed signs of protein insufficiency. When the threshold of 20 mg/dl for prealbumin was used, we found 38 patients (55%) with low prealbumin concentrations. CONCLUSION: A significant group presented signs of protein insufficiency either using prealbumin z-scores or prealbumin concentration threshold, especially in milder forms of the disease. The results of this seem to confirm the already described threshold level for prealbumin concentration, suggesting that its measurement may be important for nutritional status evaluation, preventing protein insufficiency in milder forms of phenylketonuria.