Browsing by Author "Lavinha, J"
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- Biomarkers and Genetic Modulators of Cerebral Vasculopathy in Sub-Saharan Ancestry Children With Sickle Cell AnemiaPublication . Silva, M; Vargas, S; Coelho, A; Ferreira, E; Mendonça, J; Vieira, L; Maia, R; Dias, A; Ferreira, T; Morais, A; Soares, IM; Lavinha, J; Silva, R; Kjöllerström, P; Faustino, PWe investigated biomarkers and genetic modulators of the cerebral vasculopathy (CV) subphenotype in pediatric sickle cell anemia (SCA) patients of sub-Saharan African ancestry. We found that one VCAM1 promoter haplotype (haplotype 7) and VCAM1 single nucleotide variant rs1409419_T were associated with stroke events, stroke risk, as measured by time-averaged mean of maximum velocity in the middle cerebral artery, and with high serum levels of the hemolysis biomarker lactate dehydrogenase. Furthermore, VCAM-1 ligand coding gene ITGA4 variants rs113276800_A and rs3770138_T showed a positive association with stroke events. An additional positive relationship between a genetic variant and stroke risk was observed for ENPP1 rs1044498_A. Conversely, NOS3 variants were negatively associated with silent cerebral infarct events (VNTR 4b_allele and haplotype V) and CV globally (haplotype VII). The -alpha3.7kb-thal deletion did not show association with CV. However, it was associated with higher red blood cell and neutrophil counts, and lower mean corpuscular volume, mean corpuscular hemoglobin and red cell distribution width. Our results underline the importance of genetic modulators of the CV sub-phenotype and their potential as SCA therapeutic targets. We also propose that a biomarker panel comprising biochemical, hematological, imaging and genetic data would be instrumental for CV prediction, and prevention.
- Genetic Modulators of Fetal Hemoglobin Expression and Ischemic Stroke Occurrence in African Descendant Children With Sickle Cell AnemiaPublication . Nicolau, M; Vargas, S; Silva, M; Coelho, A; Ferreira, E; Mendonça, J; Vieira, L; Kjöllerström, P; Maia, R; Silva, R; Dias, A; Ferreira, T; Morais, A; Soares, IM; Lavinha, J; Faustino, PSickle cell anemia (SCA) is an autosomal recessive monogenic disease with significant clinical variability. Cerebrovascular disease, particularly ischemic stroke, is one of the most severe complications of SCA in children. This study aimed to investigate the influence of genetic variants on the levels of fetal hemoglobin (Hb F) and biochemical parameters related with chronic hemolysis, as well as on ischemic stroke risk, in ninety-one unrelated SCA patients, children of sub-Saharan progenitors. Our results show that a higher Hb F level has an inverse relationship with the occurrence of stroke, since the group of patients who suffered stroke presents a significantly lower mean Hb F level (5.34 ± 4.57% versus 9.36 ± 6.48%; p = 0.024). Furthermore, the co-inheritance of alpha-thalassemia improves the chronic hemolytic pattern, evidenced by a decreased reticulocyte count (8.61 ± 3.58% versus 12.85 ± 4.71%; p < 0.001). In addition, our findings have confirmed the importance of HBG2 and BCL11A loci in the regulation of Hb F expression in sub-Saharan African SCA patients, as rs7482144_A, rs11886868_C, and rs4671393_A alleles are significantly associated with a considerable increase in Hb F levels (p = 0.019, p = 0.026, and p = 0.028, respectively). Concerning KLF1, twelve different variants were identified, two of them novel. Seventy-three patients (80.2%) presented at least one variant in this gene. However, no correlation was observed between the presence of these variants and Hb F level, severity of hemolysis, or stroke occurrence, which is consistent with their in silico-predicted minor functional consequences. Thus, we conclude that the prevalence of functional KLF1 variants in a sub-Saharan African background does not seem to be relevant to SCA clinical modulation.
- Mucoviscidose com Sintomatologia Respiratória no Período NeonatalPublication . Lamy, S; Pereira-da-Silva, L; Lopes, B; Pacheco, P; Lavinha, J; Mateus Marques, J; Videira-Amaral, JDescreve-se um caso de mucoviscidose com sintomatologia respiratória iniciada no período neonatal, associada a insuficiência pancreática invulgarmente precoce, o estudo da genética molecular revelou que, ao nível do gene CFTR, foi identificado na doente um composto genético das mutações FS08 e GS42X Realça-se a raridade desta forma de apresentação sendo no entanto lícito admitir-se esta entidade nosológica no diagnóstico diferencial da sindroma de dificuldade respiratória no recém-nascido. Discute-se a patogénese e alguns aspectos particulares da terapêutica instituida, os quais tem sido importantes para a melhoria da expectativa de vida de doentes com esta patologia.
- Pesquisa de Sequências do Cromossoma Y em Indivíduos com Síndroma de TurnerPublication . Ferrão, L; Lopes, L; Limbert, C; Marques, B; Boieiro, F; Marques, R; Lavinha, J; Mota, A; Gonçalves, JO síndroma de Turner (TS) tem sido descrito em associação com diversas anomalias dos cromossomas sexuais. Embora a maioria dos individuos com TS não apresentem evidência citogenética de sequências do cromossoma Y, diferentes autores consideram que algumas doentes com TS podem possuir uma linha celular minoritária contendo material do cromossoma Y, que não é detectada pela análise citogenética convencional. A identificação de moisacismos minoritários ou subrepresentados contendo o cromossoma Y é de importância fundamental em termos clínicos devido ao risco aumentado que estas doentes possuem para desenvolvimento de gonadoblastoma. No presente estudo procedeu-se à análise citogenética convencional de linfócitos de sangue periférico obtidos de 22 doentes com TS. Destas doentes, doze possuíam cariotipo 45,X, em sete foram detectados mosaicos com ou sem anomalias estruturais do cromossoma X e nas restantes três foram identificados os seguintes cariotipos: 46,X,i (X)(q10); 46,X,+mar/47,X,idic(Y),+mar e 45,X/46,X,+r. Os estudos moleculares foram realizados em DNA genómico obtido a partir de linfócitos de sangue periférico e de células de mucosa bucal, dois tecidos que derivam de folhetos embrionários diferentes, respectivamente, mesoderme e ectoderme. A pesquisa de moisacismos minoritários envolvendo o cromossoma Y foi efectuada por PCR simples e PCR nested para os seguintes loci específicos do cromossoma Y: SRY (sex determining region Y), TSPY (testis specific protein Y encoded), DYZ3 (locus centromérico) e DAZ1 (deleted in azoospermia). O uso de STSs localizados nos braços curto e longo do cromossoma Y permitiu a caracterização de um idic (Y)e de um cromossoma em anel, detectados em duas das doentes estudadas. A eleveda sensibilidade da PCR nested (1 célila masculina/125 000 células femininas) permitiu excluir a presença de moisacismos minoritários do Y em 20 das 22 doentes com TS. Na doente com um idic(Y) a análise por PCR simples foi posistiva para todos os loci estudados com excepção da região heterocromática. Este resultado permitiu identificar o ponto de quebra no braço longo entre sY158 e sY159, tendo-se confirmado por hibridação in situ de fluorescência (FISH), a duplicação da eurocromatina do braço longo, centrómero e braço curto do cromossoma Y. A caracterização do cromossoma em anel, detectado num das doentes com TS só foi possível por FISH e por PCR. Neste cromossoma, derivado de Y, foi detectada, no braço curto, a delecção da região pseudoautossómica 1 (PARY1)e, no braço longo, a delecção dos intervalos 6 e 7. Contudo, o referido cromossoma foi positivo para os loci SRY, RPS4Y, AMGY, TSPY localizados no braço curto, DYZ3 (centrómero) e, sY85, DFFRY, GY6, sY87, sY113, sY119, sY122, sY126 e RBMY1 localizados no braço longo do cromossoma Y. Este estudo permitiu, assim, excluir a presença de moisacismos minoritários do cromossoma Y em dois tecidos obtidos de 20 doentes com TS, e caracterizar por FISH e análise molecular, um idic(Y) e um cromossoma em anel, em que a natureza deste último não tinha sido identificada por análise citogenética convencional. O risco elevado de desenvolvimento de gonadoblastoma nos indivíduos com TS que possuem sequências do cromossoma Y justifica a aplicação de FISH e PCR para a caracterização de cromossomas marcadores e a utilização de PCR nested para a detecção de moisacismos minoritários do Y sempre que o material deste cromossoma não seja detectado pela análise citogenética convencional em doentes com cariotipo 45,X e/ou virilização.
- Population Genetics of IFITM3 in Portugal and Central Africa Reveals a Potential Modifier of Influenza SeverityPublication . David, S; Correia, V; Antunes, L; Faria, R; Ferrão, J; Faustino, P; Nunes, B; Maltez, F; Lavinha, J; Rebelo de Andrade, HInfluenza epidemics are a serious global public health and economic problem. The IFITM3 allele (rs12252-C) was suggested as a population-based genetic risk factor for severe influenza virus infection by A(H1N1)pdm09. We analyzed the population genetics of IFITM3 variants in the Portuguese general population (n = 200) and Central Africans (largely Angolan) (n = 148) as well as its association to influenza severity in Portuguese patients (n = 41). Seven SNPs, within the 352 bp IFITM3 amplicon around rs12252, were identified. SNP distributions in the Portuguese appeared at an intermediate level between the Africans and other Europeans. According to HapMap, rs34481144 belongs to the same linkage disequilibrium (LD) block as rs12252 and is in strong LD with rs6421983. A negative association with severe relative to mild disease was observed for allele rs34481144-A, indicating a protective effect under the dominant model. Moreover, haplotype Hap4 with rs34481144-A, not including rs12252-C, was significantly associated to mild influenza. Conversely, although with borderline significance, haplotype Hap1 with rs34481144-G, not including rs12252-C, was associated to severe disease. Moreover, in comparison to the general Portuguese population, statistical significant differences in the frequencies of the protective allele rs34481144-A in the severe disease group, the deleterious Hap1 in the mild disease group, and the protective Hap4 in the severe disease group were observed. The population attributable risk (PAR) for the targeted rs34481144 allele or genotype was of 55.91 and 64.44% in the general population and the mildly infected individuals, respectively. Implication of these variants in disease phenotype needs further validation, namely through functional analysis as is discussed.
- Profilaxia das Doenças Hereditárias do EritrócitoPublication . Lamy, S; Braga, L; Pacheco, P; Lavinha, J; Gomes Costa, G; Cordeiro Ferreira, NPretende-se esclarecer a prevalência que as doenças hereditárias do eritrócito têm não só a nível mundial e europeu mas também ao nível do nosso país e consulta de hematologia pediátrica do Hospital Dona Estefânia. São realçados os aspectos que condicionam a morbilidade associada a estas doenças crónicas, quer do ponto de vista da sua própria evolução natural como da própria terapêutica instituida. São referidas atitudes consensuais do ponto de vista profilático e terapêutico adoptadas neste tipo de doenças crónicas. Assume-se o diagnóstico pós-natal como de extrema importância, possibilitando diagnosticar-se casais de risco e implementar medidas privilegiando o aconselhamento destes casais quanto à característica genética de que são portadores e pondo à sua disposição meios de diagnóstico seguros na caracterização da sua descendência antes do nascimento (daignóstico pré-natal), com base num estudo de biologia molecular. Conclui-se realçando os programas de prevenção, sem os quais se torna impossível o decréscimo da incidência destas doenças, nomeadamente nos países de forte prevalência.
- Rastreio Neonatal de Hemoglobinopatias numa População Residente em PortugalPublication . Peres, MJ; Carreiro, MH; Machado, MC; Seixas, T; Picanço, I; Batalha, L; Lavinha, J; Martins, MCThe primary objective of newborn screening of hemoglobinopathies is the early identification of infants with sickle cell disease, as they are at increased clinical risk. Other goals include the identification of other types of clinically significant hemoglobinopathies and the detection of heterozygous carriers followed by the screening and counselling of family members. We performed a pilot study for the neonatal screening of hemoglobinopathies in 400 samples of cord blood taken from a maternity in Lisbon. We did not find any newborn with sickle cell disease. Six samples were from sickle cell heterozygotes, the respective families were studied and informed. We looked for the presence of alpha-thalassemia at birth in 100 consecutive samples of cord blood, by the presence of Hb Bart's, abnormal red blood cell indices and alpha-globin genotype. The results show an incidence of 10% of alpha-thalassemia (-alpha) carriers and 4% of triple alpha-globin gene carriers. The authors discuss the feasibility of neonatal screening of hemoglobinopathies in a Portuguese-speaking population consisting of a low prevalence of Hb S trait autoclonous group and a high prevalence immigrant minority
- Sickle cell anemia - Nitric oxide related genetic modifiers of hematological and biochemical parametersPublication . Aguiar, L; Matos, A; Gil, A; Afonso, C; Almeida, S; Braga, L; Lavinha, J; Kjollerstrom, P; Faustino, P; Bicho, M; Inácio, ASickle cell anemia (SCA) is an inherited blood disorder. SCA patients present clinical and hematologic variability that cannot be only explained by the single mutation in the beta-globin gene. Others genetic modifiers and environmental effects are important for the clinical phenotype. SCA patients present arginine deficiency that contributes to a lower nitric oxide (NO) bioactivity.
- Single-Strand Conformation Polymorphism (SSCP) Analysis of the Molecular Pathology of Hemophilia BPublication . David, D; Rosa, HA; Pemberton, S; Diniz, MJ; Campos, M; Lavinha, JIn the present study, we report the application of polymerase chain reaction-single-strand conformation polymorphism (PCR-SSCP) analysis to the screening of seven functionally important factor IX gene (FIX) regions (total length 2.66 kb) in 9 unrelated haemophilia B patients of Portuguese or African origin. In eight of the patients an altered migration pattern of single-stranded DNA was observed. Direct sequencing of the relevant DNA fragments unveiled the following sequence alterations: two novel mutations, namely FIXBarcelos Thr-380-Pro and FIXLousada 9bp insertion at position 31,309 or 31,318; five mutations previously reported in other ethnic groups (FIXPorto Arg-145-His, FIXLuanda Gly-207-Arg, FIXPenafiel Arg-248-Gln, FIXSesimbra Arg-333-Gln, FIXCascais Arg-333-Stop); and a normal variant, G-->T transvertion at position 6,596 in intron 2. We propose hypothetical models for the generation of the 9 bp duplication (FIXLousada). We have performed molecular modeling studies in order to predict the structure of the variant FIX molecules.
- The Spectrum of Mutations and Molecular Pathogenesis of Hemophilia A in 181 Portuguese PatientsPublication . David, D; Ventura, C; Moreira, I; Diniz, MJ; Antunes, M; Tavares, A; Araújo, F; Morais, S; Campos, M; Lavinha, J; Kemball-Cook, GDisease-causing alterations within the F8 gene were identified in 177 hemophilia A families of Portuguese origin. The spectrum of non-inversion F8 mutations in 101 families included 67 different alterations, namely: 36 missense, 8 nonsense and 4 splice site mutations, as well as 19 insertions/deletions. Thirty-four of these mutations are novel. Molecular modeling allowed prediction of the conformational changes introduced by selected amino acid substitutions and their correlation with the patients' phenotypes. The relatively frequent, population-specific, missense mutations together with de novo alterations can lead to significant differences in the spectrum of F8 mutations among different populations.