Browsing by Author "Batalha Reis, Ana"
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- Alpha-thalassemia due to novel deletions and complex rearrangements in the subtelomeric region of chromosome 16pPublication . Ferrão, José; Silva, Marisa; Gonçalves, Lúcia; Gomes, Susana; Loureiro, Pedro; Coelho, Andreia; Miranda, Armandina; Seuanes, Filomena; Batalha Reis, Ana; Pina, Francisca; Maia, Raquel; Kjollerstrom, Paula; Monteiro, Estela; F. Lacerda, João; Lavinha, João; Gonçalves, João; Faustino, PaulaIntroduction: Inherited deletions removing the α-globin genes and/or their upstream regulatory elements (MCSs) give rise to alpha-thalassemia, one of the most common genetic recessive disorders worldwide. The pathology is characterized by microcytic hypochromic anemia due to reduction of the α-globin chain synthesis, which are essential for hemoglobin tetramerization. Material and Methods: In order to clarify the suggestive α-thalassemia phenotype in eleven patients, we performed Multiplex Ligation-dependent Probe Amplification with commercial and synthetic engineered probes, gap-PCR, and Sanger sequencing to search for deletions in the subtelomeric region of chromosome 16p. Results: We have identified five distinct large deletions, two of them novel, and one indel. The deletions range from approximately 3.3 to 323 kb, and i) remove the whole α-globin cluster; or ii) remove exclusively the upstream regulatory elements leaving the α-globin genes structurally intact. The indel consists in the loss of MCS-R2 (HS-40), which is the most important distal regulatory element for the α-globin gene expression, and the insertion of 39 bp, seemingly resulting from a complex rearrangement involving two DNA segments (probably from chromosome 3q) bridging the deletion breakpoints with a CC-bp orphan sequence in between. Finally, in one patient no α-globin deletion or point mutation were found. This patient revealed to be a very unusual case of acquired alpha-thalassemia associated with a myelodysplastic syndrome. Conclusions: Our study widens the spectrum of molecular lesions by which α-thalassemia may occur and emphasizes the importance of diagnosing large α-zero-deletions to provide patients with appropriate genetic counseling.
- Alpha-thalassemia due to novel deletions and complex rearrangements in the subtelomeric region of chromosome 16pPublication . Ferrão, José; Silva, Marisa; Gonçalves, Lúcia; Gomes, Susana; Loureiro, Pedro; Coelho, Andreia; Miranda, Armandina; Seuanes, Filomena; Batalha Reis, Ana; Valtonen-André, Camila; Sonesson, Annika; Pina, Francisca; Maia, Raquel; Kjollerstrom, Paula; Monteiro, Estela; F. Lacerda, João; Lavinha, João; Gonçalves, João; Faustino, PaulaIntroduction: Inherited deletions removing the α-globin genes and/or their upstream regulatory elements (MCSs) give rise to alpha-thalassemia, one of the most common genetic recessive disorders worldwide. The pathology is characterized by microcytic hypochromic anemia due to reduction of the α-globin chain synthesis, which are essential for hemoglobin tetramerization. Material and Methods: In order to clarify the suggestive α-thalassemia phenotype in eleven patients, we performed Multiplex Ligation-dependent Probe Amplification with commercial and synthetic probes, gap-PCR, and Sanger sequencing to search for deletions in the subtelomeric region of chromosome 16p. Results: We have identified six distinct large deletions, three of them novel, and one indel. The deletions range from approximately 3.3 to 323 kb, and i) remove the whole α-globin cluster; or ii) remove exclusively the upstream regulatory elements leaving the α-globin genes structurally intact. The indel consists in the loss of MCS-R2 (HS-40), which is the most important distal regulatory element for the α-globin gene expression, and the insertion of 39 nt, seemingly resulting from a complex rearrangement involving two DNA segments (probably from chromosome 3q), bridging the deletion breakpoints with a CC-bp orphan sequence in between. Finally, in one patient no α-globin deletion or point mutation were found. This patient revealed to have acquired alpha-thalassemia associated with a myelodysplastic syndrome. Conclusions: Our study widens the spectrum of molecular lesions by which α-thalassemia may occur and emphasizes the importance of diagnosing large α0-deletions to provide patients with appropriate genetic counseling.
- Análise retrospetiva do desempenho dos participantes no Programa de Morfologia do Sangue Periférico - PNAEQ 2012-2017Publication . Silva, Susana Pereira; Pereira, Edna; Correia, Helena; Miranda, Armandina; Cardoso, Ana; Silva, Cândido; Ismail, Sara; Barreira, Rui; Miranda, Ana; Batalha Reis, Ana; Faria, Ana PaulaO exame morfológico do sangue periférico é essencial para o diagnóstico clínico de doenças hematológicas e doenças não hematológicas com expressão morfológica no sangue periférico. A avaliação do desempenho dos profissionais deve ser uma prática implementada pelos laboratórios. A participação em programas de avaliação externa da qualidade, em que são enviadas amostras de doentes selecionadas pelos membros do Grupo de Trabalho de Hematologia do Programa Nacional de Avaliação Externa da Qualidade (PNAEQ), permite a avaliação e formação tendo como objetivo a melhoria do desempenho dos profissionais. No programa de Morfologia de Sangue Periférico do PNAEQ são enviados três ensaios anuais com três amostras cada. O Grupo de Trabalho de Hematologia foi formalizado em 2013 e conta com a colaboração de peritos nacionais, dos laboratórios de Centros Hospitalares Lisboa Norte e Ocidental e do Instituto Português de Oncologia de Lisboa, que contribuem voluntariamente com amostras de doentes, assim como com comentários complementares formativos. O objetivo deste trabalho é avaliar o desempenho dos participantes de laboratórios hospitalares e de ambulatório, no período 2012-2017, quanto à identificação das alterações morfológicas e hipóteses de diagnóstico[1] nas amostras esfregaços de sangue periférico.
- External Quality Assessment in peripheral blood morphology - PNAEQ experiencePublication . Miranda, Armandina; Correia, Helena; Silva, Susana Pereira; Pereira, Edna; Cardoso, Ana; Silva, Cândido; Ismail, Sara; Barreira, Rui; Miranda, Ana; Batalha Reis, Ana; Faria, Ana PaulaPeripheral blood morphology is a very important tool for the clinical diagnosis in haematology disorders. The National External Quality Assessment Program (PNAEQ), aims to promote EQA programs, using Expert Working Groups as methodology (WG). The Haematology WG was formalized in 2013 and has the collaboration of national experts, namely from hospital and oncology entities, who voluntarily contribute with samples and case study selection, as well as in monitoring and evaluation of the results, aiming to a continuous improvement of participants' performance. The aim of this work was the evaluation of participating hospital and ambulatory laboratories performance, in the period between 2015 and 2017, regarding the identification of the morphological alterations and diagnostic hypothesis(1) for the peripheral blood smear sent.
- Unusual molecular mechanisms in the origin of alpha-thalassemiaPublication . Ferrão, José; Silva, Marisa; Gonçalves, Lúcia; Gomes, Susana; Loureiro, Pedro; Coelho, Andreia; Miranda, Armandina; Seuanes, Filomena; Batalha Reis, Ana; Pina, Francisca; Maia, Raquel; Kjollerstrom, Paula; Monteiro, Estela; F. Lacerda, João; Lavinha, João; Gonçalves, João; Faustino, PaulaHemoglobin (Hb) is a protein responsible for oxygen transportation from lungs to the entire body. It is composed by four globular subunits - the globins - each with a central core containing a heme molecule. Globins are encoded by the α- and β-globin gene clusters located at 16p13.3 and 11p15.5, respectively. The pattern of globin gene expression during development is precisely controlled by the interaction of cis-regulatory genomic regions (located in close proximity to and far from genes) with trans-activating/silencing factors within permissive chromatin domains. Distally upstream of the α-globin genes there are four multispecies conserved sequences (MCS-R1 to R4) which are critical for the expression of the downstream globin genes. Deletions removing the α-globin genes and/or their distal MCSs give rise to α-thalassemia, one of the most common genetic recessive disorders worldwide, due to a reduced rate of α-globin chain synthesis. The severity of the pathology is variable ranging from a very mild microcytic hypochromic anemia to a moderately severe anemia associated with the formation of β4 tetramers resulting in HbH disease or an even higher reduction or complete absence of α-chains resulting in hemoglobin Bart’s hydrops fetalis, a condition generally incompatible with life. The main objectives of this work were to characterize the molecular lesions underlying ten Portuguese cases of unusual α-thalassemia/HbH disease and to understand their origin and functional consequences. After exclusion the most frequent molecular lesions associated with α-thalassemia, Multiplex Ligation-dependent Probe Amplification (MLPA) using the SALSA MLPA P140B HBA kit (MCR-Holland) was used to search for DNA deletions in the subtelomeric region of chromosome 16p. Additionally, specifically designed synthetic MLPA probes, as well as gap-PCR and Sanger sequencing were performed for more accurate deletion breakpoint mapping. We have found five distinct deletions and one indel, all in heterozygosity. The deletions range from approximately 3.3 to 323 kb and two of them are novel. The three larger deletions remove the entire α-globin cluster whereas the others remove totally or partially the distal regulatory elements keeping the α-globin genes structurally intact. The indel comprises the deletion of the MCS-R2 regulatory element and the insertion of a singular 39 bp DNA fragment possibly originating from a complex rearrangement involving chromosome 3. Finally, no α-globin gene cluster deletion or point mutation were found in a patient who revealed to be a very unusual case of acquired alpha-thalassemia associated with a myelodysplastic syndrome. Our study widens the spectrum of molecular lesions and unusual molecular mechanisms by which α-thalassemia/HbH may occur and emphasizes the importance of diagnosing large α0-deletions to provide patients with appropriate genetic counseling.