Percorrer por autor "Gaspar, Gisela"
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- Alfa-talassémia delecional e fenótipo hematológico: parâmetros associados às diferentes deleções na casuística de 2015 a 2019Publication . Gaspar, Gisela; Ramalho, Rita de Mira; Seuanes, Filomena; Feliciano, Carla; Duarte, Guida; Copeto, Sandra; Costa, Alcina; Santos, João Xavier; Miranda, ArmandinaAs talassémias são caracterizadas por um desequilíbrio quantitativo nas cadeias globinicas devido à redução ou supressão da síntese de uma das cadeias. Foram avaliados retrospetivamente os resultados de 496 casos suspeitos de α-talassémia delecional e correlacionados com os dados hematológicos. A pesquisa de deleções causadoras de α-talassémia foi efetuada por Gap e Multiplex Gap-PCR. A maioria dos casos (n=190) apresentou um genótipo normal (αα /αα), seguido de heterozigotia (-α 3 ,7 /αα) (n=148) e homozigotia (-α 3 ,7 /α 3 ,7 ) (n=141) para a deleção de 3,7kb. Detetaram-se ainda 5 casos de heterozigotia para a deleção de 4,2Kb (-α 4,2 /αα), 4 de dupla heterozigotia ( α 3 ,7 /α 4,2 ), 7 de heterozigotia α 0 (-- S E A /αα ), e 1 de Hb H (-- S E A /-α 3 ,7 ). Os resultados evidenciaram que o VGM e o HGM são excelentes índices hematológicos de rastreio e seleção dos testes moleculares, sendo o seu valor tanto mais baixo quanto maior o número de genes delecionados. Os resultados obtidos são ainda concordantes com o descrito na literatura e reforçam que o valor de cut-off de 25 pg (HGM), tem sensibilidade adequada para inferir da presença de uma deleção α 0 -talassémia. A deteção da deleção α 0 assume particular importância na prevenção da ocorrência de Hb Bart’s na descendência de um casal de portadores. O diagnóstico de α-talassémia é efetuado por métodos moleculares, no entanto os índices hematológicos são importantes marcadores preditivos do número de genes alfa delecionados e da relação fenótipo / genótipo.
- Ancestry of the major long-range regulatory site of the α-globin genes in the Portuguese population with the common 3.7 kb α-thalassemia deletionPublication . Pena, Rita; Lopes, Pedro; Gaspar, Gisela; Miranda, Armandina; Faustino, PaulaBackground: The α-Major Regulatory Element (α-MRE), also known as HS-40, is located upstream of the α-globin gene cluster and has a crucial role in the long-range regulation of the α-globin gene expression. This enhancer is polymorphic and several haplotypes were identified in different populations, with haplotype D almost exclusively found in African populations. The purpose of this research was to identify the HS-40 haplotype associated with the 3.7 kb α-thalassemia deletion (-α3.7del) in the Portuguese population, and determine its ancestry and influence on patients' hematological phenotype. Methods and results: We selected 111 Portuguese individuals previously analyzed by Gap-PCR to detect the presence of the -α3.7del: 50 without the -α3.7del, 34 heterozygous and 27 homozygous for the -α3.7del. The HS-40 region was amplified by PCR followed by Sanger sequencing. Four HS-40 haplotypes were found (A to D). The distribution of HS-40 haplotypes and genotypes are significantly different between individuals with and without the -α3.7del, being haplotype D and genotype AD the most prevalent in patients with this deletion in homozygosity. Furthermore, multiple correspondence analysis revealed that individuals without the -α3.7del are grouped with other European populations, while samples with the -α3.7del are separated from these and found more closely related to the African population. Conclusion: This study revealed for the first time an association of the HS-40 haplotype D with the -α3.7del in the Portuguese population, and its likely African ancestry. These results may have clinical importance as in vitro analysis of haplotype D showed a decrease in its enhancer activity on α-globin gene.
- Ancestry of the major long-range regulatory site of the α-globin genes in the Portuguese population with the common 3.7kb α-thalassemia deletionPublication . Pena, Rita; Lopes, Pedro; Gaspar, Gisela; Miranda, Armandina; Faustino, PaulaThe α-major regulatory element (known as HS-40) has a crucial role in the long-range regulation of the α-globin gene expression. This element is genetically polymorphic and six haplotypes (A to F) have been identified in different populations, with haplotype D almost exclusively found in African populations. This study aimed to identify the HS-40 haplotype associated with the common 3.7kb α-thalassemia deletion (-α3.7del) in the Portuguese population, and investigate its ancestry. We searched for the -α3.7del in 111 selected Portuguese individuals by Gap-PCR. In addition, a DNA fragment containing the HS-40 was amplified by PCR and Sanger sequenced. Statistical analysis was performed using R software. Fifty individuals have the wild-type α-globin genotype (group I), 34 are heterozygous for the -α3.7del (group II) and 27 are homozygous (group III). Regarding the HS-40, four haplotypes were found (A to D). The distribution of HS-40 haplotypes and genotypes are significantly different between groups with and without the -α3.7del (p<0.001), being haplotype D and genotype AD the most prevalent in group III. Furthermore, multiple correspondence analysis revealed that individuals without the -α3.7del are grouped with other European populations, while samples with the -α3.7del are split from these and found more related to the African population. This study revealed for the first time an association of a specific HS-40 haplotype with the -α3.7del in the Portuguese population, and its likely African ancestry. These results may have a clinical importance as in vitro analysis of haplotype D showed a descrease in its enhancer activity on α-globin genes.
- Ancestry of the α-MRE Associated with the 3.7kb α-Thalassemia Deletion in the Portuguese PopulationPublication . Pena, Rita; Lopes, Pedro; Gaspar, Gisela; Miranda, Armandina; Faustino, PaulaThe α-major regulatory element (α-MRE), also known as HS-40, is located upstream of the α-globin gene cluster and has a crucial role in the long-range regulation of the α-globin gene expression. It is genetically polymorphic and six haplotypes (A to F) have been identified in different populations. The D haplotype was primary described in African populations and is nearly absent in other populations. The aims of this study were to identify the α-MRE haplotype associated with the common 3.7kb α-thalassemia deletion (-α3.7del) in the Portuguese population, and to investigate its ancestry. We searched for the -α3.7del in 111 selected Portuguese individuals by Gap-PCR. In addition, a DNA fragment containing the α-MRE was amplified by PCR and Sanger sequenced. Statistical analysis was performed using R software. Fifty individuals have the wild-type α-globin genotype (group I), 34 are heterozygous for the -α3.7del (group II) and 27 are homozygous (group III). Regarding the α-MRE, four haplotypes were found (A to D). The ancestral A haplotype is predominant in all groups. The B haplotype is the second most frequent in groups I and II, whereas in group III haplotype D is the second most prevalent. Concerning genotypes, the α-MRE AA and AB are the most common in group I, while genotype AD is more prevalent in group III. In fact, 71.4% of AD individuals are homozygous for the -α3.7del. Moreover, the distribution of α-MRE haplotypes and genotypes are significantly different between groups with and without the -α3.7del (p<0.001). Furthermore, multiple correspondence analysis revealed that individuals without the -α3.7del are grouped with other European populations, while samples with the -α3.7del are split from these and found to be more closely related to the African population. This study revealed for the first time an association of a specific α-MRE haplotype with the common -α3.7del in the Portuguese population, and its likely African ancestry. These results may have clinical importance as the D haplotype has an alteration in the consensus sequence for the AP-1/NF-E2 binding site and in vitro experiments showed a decrease in its enhancer activity on α-globin genes.
- Avaliação de diferenças bioquímicas entre indivíduos diabéticos com e sem variantes patogénicas causadores de MODY. (PO 47)Publication . Vaz, Margarida; Gaspar, Gisela; Agapito, Ana; Neves, Ana Carolina; Bogalho, Ana Paula; Almeida, Bruno; Pereira, Carla; Fonseca, Fernando; Lobarinhas, Goreti; Luiz, Henrique Vara; Duarte, João Sequeira; Sampaio, Maria de Lurdes; Dario, Paulo; Bourbon, MafaldaA diabetes tipo MODY (Maturity-onset diabetes of the young) é um tipo de diabetes causada por mutações em um único gene. Existe 14 genes associados a essa doença, no entanto, a maioria dos casos de MODY é causada por alterações nos genes GCK, HNF1A, HNF1B e HNF4A. Cada subtipo desta patologia apresenta características fenotípicas, metabólicas e complicações para a saúde distintas o que exige uma adequação terapêutica diferente. Contudo a grane maioria dos casos de MODY é erroneamente diagnosticada como diabetes tipo 1 ou tipo 2, o que prejudica o diagnóstico do doente. O objetivo deste trabalho consiste na caracterização bioquímica dos participantes do Estudo Molecular de diabetes tipo MODY com base nos valores de glicémia e hemoglobina A1c inicial, indicados nos inquéritos do estudo, pelos médicos que os referenciaram, para perceber se estes valores são ou não um bom indicador de diabetes tipo MODY. Para tal foram analisados os valores de 76 participantes do estudo, com e sem mutação. Para análise estatística dos valores utilizou-se o Rstudio. Com os testes de Shapiro e Wilcox para avaliou-se e distribuição das amostras, bem como as diferenças entre os dois grupos. Os resultados desta análises não revelaram diferença estatística significativa (valor p=0.5) entre os valores de glicémia inicial dos participantes do estudo com mutação e sem mutação, nem com os valores de hemoglobina A1c (valor p= 0.19). Os resultados apresentados sustentam o argumento de que não é possível identificar corretamente pacientes com diabetes tipo MODY apenas com base nos resultados bioquímicos da glicémia e da hemoglobina A1c e que o diagnóstico genético é essencial para que o conceito de medicina personalizada seja uma realidade acessível aos pacientes diabéticos em Portugal.
- Deficiência em Desidrogenase da Glicose-6-fosfato – Caracterização MolecularPublication . Gaspar, Gisela; Miranda, ArmandinaFolheto técnico sobre a caracterização molecular da Deficiência em Desidrogenase da Glicose-6-fosfato.
- Deletional alpha-thalassemia and hematological phenotype: predictive parameters of different deletionsPublication . Gaspar, Gisela; Ramalho, Rita de Mira; Seuanes, Filomena; Feliciano, Carla; Duarte, Guida; Copeto, Sandra; Costa, Alcina; Santos, João Xavier; Miranda, ArmandinaIntroduction: Thalassemias are characterized by a quantitative imbalance of the globin chains due to the reduction or suppression of the synthesis of one of the globin chains.The hematological tests usually used as indicative for the investigation of α-thalassemia are the blood count with MCV (Mean Cell Volume) < 80 fL and/or MCH (Mean Cell Hemoglobin) < 27 pg and normal Hb A2 (< 3.5%). Aim: This study aimed to correlate the different deletional α-thalassemia genetic alterations with the corresponding hematological phenotype, based on casuistry from 2015 to 2019. Methodology: Was evaluated retrospectively 496 cases suspected of deletional α-thalassemia from 2015 to 2019 and correlated them with the hematological data available. We searched for α-thalassemia deletions by Gap-PCR and Multiplex Gap-PCR. Haematological evaluation was carried out by the erythrogram, Hb isoelectric focusing and quantification of Hb A2 and Hb F (Ion exchange high performance liquid chromatography). The statistical analysis of the results was carried out through calculating the mean, standard deviation, median, and t-Student test, with a significance level of 0.05. Results and discussion: Most patients (n=190) had a normal genotype (αα/αα), followed by heterozygosity (-α3.7/αα) (n=148) and homozygosity (-α3.7/α3.7) (n=141) for the 3.7kb deletion. We also detected 5 cases of heterozygosity for the 4.2Kb deletion (-α4.2/αα), 4 of double heterozygosity (α3.7/α4.2), 7 heterozygosity α0 (--SEA /αα) and 1 of HbH (--SEA/-α3.7). The results showed that the MCV and the MCH are excellent hematological indices for screening and selection of patients for molecular testing (their value being the lower the greater the number of deleted genes). Our results are in line with those described in the literature and reinforce that the cut-off value of 25 pg (MCH) is sensitive enough to infer the presence of α0 -thalassemia deletion. The detection of the α0 deletion is very important in preventing the occurrence of Hb Bart's in the offspring of a carrier couple. The diagnosis of deletional α-thalassemia is realised by genetic testing, however hematological indices are relevant predictive markers of the number of deleted alpha genes and the phenotype /genotype correlation.
- Diabetes Tipo MODY – Caracterização MolecularPublication . Gaspar, Gisela; Miranda, ArmandinaFolheto técnico sobre caracterização molecular da Diabetes Tipo MODY.
- Diagnóstico genético da diabetes tipo MODY (Maturity-onset diabetes of the young) em PortugalPublication . Gaspar, GiselaA diabetes tipo MODY (Maturity-onset diabetes of the young) é um tipo de diabetes melitus autossómica dominante com início antes dos 25 anos de idade and a primary defect in pancreatic beta-cell function. Muitos dos doentes com MODY poderão estar erradamente classificados como tendo diabetes tipo 1 ou diabetes tipo 2 e cerca de 2% destes doentes poderão ser MODY. Estima-se que dos 600.000 diabéticos existentes em Portugal, cerca de 12.000 possam ser diabéticos do tipo MODY. Os diabéticos MODY2 apresentam hiperglicémia ligeira e estável desde o nascimento e podem se assintomáticos. Por outro lado, os doentes com MODY3 apresentam uma alteração na produção de insulina, que resulta frequentemente numa hiperglicémia grave e progressiva na idade adulta. Os subtipos MODY2 and MODY3 são os mais comuns na Europa. Os diferentes subtipos MODY podem apenas ser determinados através do diagnóstico molecular. O diagnóstico genético pode alterar o prognóstico e o tratamento da doença, uma vez que os doentes com mutações no gene GCK raramente necessitam de tratamento farmacológico enquanto que os doentes com mutações nos genes HNF1A e HNF4A são sensíveis à sulfonilureia. O objetivo deste Trabalho foi caracterizar a alteração genética associada à MODY para cada doente e seus familiares. Foram estudados 75 doentes com diagnóstico clínico de MODY 42 familiares. O estudo molecular foi feito por sequenciação direta e a pesquisa de grandes rearranjos por MLPA para os genes GCK (MODY2), HNF1A (MODY3), HNF4A (MODY1) e HNF1B (MODY5). Foram identificadas variantes patogénicas em 34% dos casos index, sendo 44% no gene GCK, 32% no gene HNF1A, 20% no gene HNF1B e 4% no gene HNF4A. O diagnóstico genético da diabetes tipo MODY permite a classificação do subtipo MODY, define o prognóstico da doença, auxilia na decisão terapêutica e define o risco para os familiares testados.
- Diagnóstico genético da diabetes tipo MODY na população portuguesaPublication . Gaspar, Gisela; Seuanes, Filomena; Duarte, João S.; Rodrigues, Dircea; Moreno, Carolina; Gouveia, Sofia; Lobarinhas, Goreti; Bogalho, Paula; Agapito, Ana; Bourbon, Mafalda