Browsing by Author "Gomes, Susana"
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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.
- Congenital adrenal hyperplasia in paediatric age: molecular analysis of the CYP21A2 gene and implications for genetic counsellingPublication . Gomes, Susana; Silva, Júlia; Pereira-Caetano, Iris; Lopes, Lurdes; Limbert, Catarina; Amaral, Daniela; Pina, Rosa; Kay, Teresa; Sampaio, Lurdes; Pereira, Carla; Moldovan, Oana; Berta, Ana; Rebelo, Irene; Gaspar, Isabel; Cidade Rodrigues, José; Lina, Ramos; Ramos, Fabiana; Dinis, Isabel; Cardoso, Rita; Mirante, Alice; Gonçalves, JoãoIntroduction: Congenital adrenal hyperplasia(CAH) is due to 21-hidroxilase deficiency(21-OHD) in about 95% of the cases. 21-OH is encoded by CYP21A2 gene, and most frequent mutations occurring in CYP21A2 are due to gene conversions originated from its pseudogene(CYP21A1P). The clinical severity of CAH is associated with the impairment of 21-OH activity, which is directly related with the molecular defect. CAH is classified as classic salt-wasting(SW) and simple virilising(SV) forms, and nonclassic(NC) form of the disease. SW and SV are usually diagnosed after birth or during the first years of life, respectively, while most cases of NC-CAH are diagnosed during infancy, puberty or until adult age. Here we present the molecular results performed in paediatric patients with CAH.
- Congenital adrenal hyperplasia with a CYP21A2 deletion overlapping the tenascin-X gene: an atypical presentationPublication . Ivo, Catarina Rodrigues; Fitas, Ana Laura; Madureira, Inês; Diamantino, Catarina; Gomes, Susana; Gonçalves, João; Lopes, LurdesObjectives: Congenital Adrenal Hyperplasia (CAH) is a group of genetic diseases characterized by impaired cortisol biosynthesis. 95% of CAH cases result from muta tion in the CYP21A2 gene encoding 21-hydroxilase. TNX-B gene partially overlaps CYP21A2 and encodes a matrix protein called Tenascin-X (TNX). Complete tenascin defi ciency causes Enlers-Danlos syndrome (EDS). A mono allelic variant called CAH-X CH-1 was recently described, resulting from a CYP21A2 complete deletion that extends into the TNXB. This haploinsufficiency of TNX may be associated with a mild hypermobility form of EDS, as well as other connective tissue comorbidities such as hernia, cardiac defects and chronic arthralgia. Case presentation: We report four patients heterozygous for a CAH-X CH-1 allele that do not present clinical mani festations of the EDS. Conclusions: All CAH patients, carriers of these TNXA/ TNXB chimeras, should be evaluated for clinical manifes tations related to connective tissue hypermobility, cardiac abnormalities and other EDS features, allowing for better clinical surveillance management
- CYP21A2 gene duplication with a severe pathogenic variant is a benign allele that does not confirm clinical suspicions of 21-hydroxylase deficiencyPublication . Gomes, Susana; Silva, Júlia; Pereira-Caetano, Iris; Gonçalves, JoãoIntroduction: Congenital Adrenal Hyperplasia (CAH), one the most common autosomal recessive disorders, is regularly managed during genetic counselling (GC). The coding gene (CYP21A2) for 21-hydroxylase (21-OH), is located (in cis) with its pseudogene (CYP21A1P) in the RCCX cluster (6p21.3) and, the most common structure of this cluster comprises a single copy of each one. However, genotypes associated with CYP21A2 duplications can be detected in individuals during familial and/or pre-conceptional studies. In this duplicated alleles, the severe variant c.955C>T p.(Glu319*) is frequently detected, but is usually present in the proximal CYP21A2 copy. This means, that even in the presence of a severe variant, its allele is not pathogenic. Therefore, the aim of this work is to emphasize the importance of a better strategy of molecular analysis and an accurate interpretation of its results, in order to establish a correct genotyping of family members and partners, and provide a more reliable genetic counselling.
- CYP21A2 gene mutations, its nature and frequency in a paediatric Portuguese cohort with congenital adrenal hyperplasiaPublication . Rosmaninho-Salgado, Joana; Caetano, Joana Serra; Gomes, Susana; Pereira-Caetano, Iris; Cardoso, Rita; Dinis, Isabel; Ramos, Lina; Ramos, Fabiana; Carvalho, Ana Luisa; Garabal, Ana; Sá, Joaquim; Maia, Sofia; Sousa, Sérgio; Saraiva, Jorge; Gonçalves, João; Mirante, AliceIntroduction: The most common cause of congenital adrenal hyperplasia (CAH) is 21-hydroxylase deficiency (21-OHD) caused by alterations in CYP21A2 gene. The clinical phenotypes of this autosomal recessive disease are classified as classic (saltwasting and simple virilizing) and non-classic forms of CAH. The severity of the disease is directly related with the impairment of the 21-OH enzymatic activity. Genetic testing can confirm the disease and is crucial for familial studies and genetic counseling. Aim: The aim of this work was to perform the clinical and molecular characterization of the patients observed at the Hospital Pediátrico de Coimbra (Portugal) with the clinical suspecion of CAH. Methods: Retrospective analysis of patient medical records of all cases observed in our hospital with suspicion of CAH and detailed literature comparison. CYP21A2 molecular analysis had been performed in 81 unrelated Portuguese patients (51 female, 30 males) with clinical and endocrine laboratorial findings suggestive of CAH, using mini-sequencing, restriction enzyme digestion, Sanger sequencing or/and multiplex ligation-dependent probe amplification (MLPA). Results: CYP21A2 variants were identified in 74/81 (91%) of the patients. Homozygosity for CYP21A2 was found in 39.2% (29/74) of the patients while 55.4% (41/74) were compound heterozygous and, in 5.4% of the cases (4/74), only one pathogenic variant was identified. The most frequent alterations were p.Val281Leu, g.655A/C>G (splicing variant) and p.Ile172Asn, that account for more than 50% of the alleles of this patient’s cohort. All variants were already described except a novel missense variant identified in a salt-wasting patient, g.1173T>C(p.Trp201Arg). The rare variant p.Gly424Ser which was detected in one patient had been previously associated with a possible founder effect in Brazil and the splicing variant g.391G>A, only described in the Portuguese population. Conclusion: Our study provides a detailed clinical and molecular characterization of a large cohort of CAH Portuguese patients. The overall concordance between the clinical phenotype and the inferred phenotype (based on genotype) was 90%.
- Distribuição temporal e geográfica da leptospirose humana diagnosticada em indivíduos residentes no norte de Portugal, 2014-2019Publication . Moura, Sofia; Rio, Carla; Gomes, Susana; Silva, Anabela SantosEm Portugal, a leptospirose humana é considerada uma doença de declaração obrigatória (DDO). De acordo com o relatório DDO 2013- -2016, a área geográfica de intervenção da ARS Norte é a segunda área do país com maior número de casos notificados de leptospirose em humanos. O objetivo deste estudo foi analisar a distribuição temporal e geográfica dos casos de leptospirose humana identificados em indivíduos residentes na região norte de Portugal, no período de 2014 a 2019, e que foram estudados no Centro de Saúde Pública Doutor Gonçalves Ferreira do Instituto Nacional de Saúde Doutor Ricardo Jorge. Realizou-se um estudo retrospetivo de 72 indivíduos com resultado positivo para pesquisa de anticorpos IgM para Leptospira spp. O maior número de casos foi registado em 2014 e o menor em 2019, 18 e 5 casos respetivamente. Em relação à distribuição por mês de diagnóstico laboratorial, verificou-se um maior número de casos diagnosticados entre os meses de junho e novembro (73,6%). Quanto à d istribuição geográfica por concelho de residência, o concelho que apresentou maior número de casos foi Vila Nova de Gaia (n=8). Do total de indivíduos diagnosticados com leptospirose humana, 79,1% residiam em freguesias classificadas como predominantemente ou mediamente urbanas. Os resultados obtidos revelaram uma assimetria na distribuição dos casos de leptospirose humana, notando-se uma maior frequência nos meses de verão/outono e em áreas predominantemente/mediamente urbanas. Este estudo é mais um contributo para o conhecimento da epidemiologia e dinâmica de transmissão da leptospirose em humanos na região norte de Portugal podendo, desta forma, ser útil para o desenvolvimento de estratégias de prevenção e controlo da doença.
- Eleven years experience of being under external quality assessment for the molecular genetic diagnosis of hereditary haemochromatosis HFE-associated and accreditation under ISO 15189Publication . Loureiro, Pedro; Gomes, Susana; Torgal, Helena; Isidro, Glória; Gonçalves, JoãoLaboratory quality is continuously present in our daily practice of molecular diagnosis in human genetics. Our participation in external quality assessment (EQA), specially with EMQN, gave us the opportunity to improve the reports of our genetic tests, to compare our performance/scores with other European laboratories, and to be permanently updated with the most recent recommendations for best practice in human molecular diagnosis. Since 2005, our lab has been participating in the EMQN external quality assessment program for the molecular diagnosis of hereditary haemochromatosis HFE-associated (HH-HFE). Since then, our score regarding the genotyping category has achieved every year the highest marks (2.0), while for the interpretation category, in two years, the mean score was 1.75. These scores lead us to improve the “interpretation section” of our reports in order to give the best result to the physicians and patients. In addition of a correct genotyping, the report “interpretation section” is particularly important, it should include the main suggestions for the best patient’s clinical management: i) immediate impact of the result for the patient, ii) patient’s clinical follow-up and other diagnostic options, iii) long term-impact (specially in predictive tests), iv) relevance of the result for relatives and, v) recommendations of genetic counselling. In accordance with OCDE disease specific guidelines for quality assurance in molecular genetic testing, and with the requirements of ISO 15189, in 2014 we were the first Portuguese laboratory accredited by IPAC, for HH-HFE - variants p.H63D and p.C282Y, and other genetic tests (http://www.ipac.pt/pesquisa/ ficha_15189.asp?id=E0015). Accreditation under the International Standard ISO 15189 is challenging but contributes to introduce improvements in our current practice because it comprises “management requirements” (e.g. quality management system, external services and supplies, preventive and corrective actions, control of records) and “technical requirements” (e.g. accommodation and environmental conditions, laboratory equipment, reagents and consumables, training and qualifications of personnel, examination processes, results reporting). Accreditation enhances laboratory quality at different levels, gives credibility, competency and confidence, but primarily contributes to a better patient’s clinical diagnosis reducing the turnaround time, patient management and treatment, and genetic counselling.
- Espectro de alterações moleculares detetadas no gene CYP21A2 associadas a deficiência em 21 hidroxilasePublication . Gomes, Susana; Pereira-Caetano, Iris; Lopes, Maria Lurdes; Limbert, Catarina; Amaral, Daniela; Pina, Rosa; Antunes, Diana; Carvalho, Inês; Kay, Teresa; Sampaio, Lurdes; Pereira, Carla; Moldovan, Oana; Berta, Ana; Rebelo, Irene; Gaspar, Isabel; Cardoso, Helena; Rodrigues, José Cidade; Ramos, Lina; Ramos, Fabiana; Dinis, Isabel; Cardoso, Rita; Mirante, Alice; Gonçalves, JoãoA maioria dos doentes com hiperplasia suprarrenal congénita (HSC) apresenta alterações moleculares no gene CYP21A2, o qual codifica a enzima 21-hidroxilase (21-OH). Os doentes com a forma clássica de deficiência em 21-OH (21-OHD) apresentam a síntese de cortisol diminuída no córtex adrenal e, os casos mais graves, também apresentam deficiência de aldosterona. As mulheres com 21-OHD grave apresentam excesso de andrógenos desde a sua vida fetal conduzindo à virilização dos órgãos genitais externos. Tanto homens como mulheres com 21-OHD completa não sintetizam a aldosterona e, consequentemente, logo após o nascimento, podem desenvolver crises de perda de sal se não forem corretamente diagnosticados e tratados. A 21- OHD não clássica é devida à deficiência parcial em 21-OH, os fenótipos clínicos são menos graves, as mulheres não apresentam virilização dos genitais externos ao nascimento, e geralmente os sinais relativos a excesso de androgénios podem surgir durante a infância ou até mais tarde (durante ou após a puberdade). Neste trabalho descrevem-se as alterações e os genótipos mais frequentes encontrados em doentes portugueses não adultos com 21-OHD. As alterações mais frequentes encontradas na forma clássica da HSC são c.293-13C> G, diferentes deleções/quimeras/conversões génicas do gene CYP21A2 e c.518T> A, enquanto na 21-OHD não-clássica a variante c.844G> T é a mais frequente. Estes resultados contribuem para um diagnóstico correto e uma melhor gestão clínica dos doentes, para o seu aconselhamento genético e para oferecer o diagnóstico pré-natal a casais com risco de ter filhos afetados com a forma clássica de 21-OHD.
- Genética molecular das hemoglobinopatias no Departamento de Genética Humana do INSA: uma trajetória de contributos para a ciência e para a sociedadePublication . Faustino, Paula; Loureiro, Pedro; Gomes, Susana; Lopes, Pedro; Gonçalves, João
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