Browsing by Author "Lemos, M"
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- A Common Variant in the CDK8 Gene Is Associated with Sporadic Pituitary Adenomas in the Portuguese Population: a Case-Control StudyPublication . Gaspar, L; Gonçalves, C; Fonseca, F; Carvalho, D; Cortez, L; Palha, A; Barros, I; Nobre, E; Duarte, J; Amaral, C; Bugalho, MJ; Marques, O; Pereira, B; Lemos, MThe majority of pituitary adenomas occur in a sporadic context, and in the absence of known genetic predisposition. Three common variants at the NEBL (rs2359536), PCDH15 (rs10763170) and CDK8 (rs17083838) loci were previously associated with sporadic pituitary adenomas in the Han Chinese population, but these findings have not yet been replicated in any other population. The aim of this case-control study was to assess if these variants are associated with susceptibility to sporadic pituitary adenomas in the Portuguese population. Genotype and allele frequencies were determined in 570 cases and in 546 controls. The CDK8 rs17083838 minor allele (A allele) was significantly associated with sporadic pituitary adenomas, under an additive (odds ratio (OR) 1.73, 95% confidence interval (CI) 1.19-2.50, p = 0.004) and dominant (OR 1.82, 95% CI 1.24-2.68, p = 0.002) inheritance model. The NEBL rs2359536 and PCDH15 rs10763170 variants were not associated with the overall risk for the disease, although a borderline significant association was observed between the PCDH15 rs10763170 minor allele (T allele) and somatotrophinomas (dominant model, OR 1.55, 95% CI 1.02-2.35, p = 0.035). These findings suggest that the CDK8 rs17083838 variant, and possibly the PCDH15 rs10763170 variant, may increase susceptibility to sporadic pituitary adenomas in the Portuguese population.
- A Novel BCR-ABL1 Mutation in a Patient with Philadelphia Chromosome-Positive B-Cell Acute Lymphoblastic LeukemiaPublication . Vinhas, R; Lourenço, A; Santos, S; Lemos, M; Ribeiro, P; Botelho de Sousa, A; Viana Baptista, P; Ramos Fernandes, APhiladelphia chromosome-positive acute lymphoblastic leukemia (Ph+ ALL) represents the most common genetic subtype of adult ALL (20%-30%) and accounts for approximately 50% of all cases in the elderly. It has been considered the subgroup of ALL with the worst outcome. The introduction of tyrosine kinase inhibitors (TKIs) allows complete hematologic remission virtually in all patients, with improved disease-free survival and overall survival. Nevertheless, the emergence of resistant mutations in BCR-ABL1 may require different TKI strategies to overcome the patient's resistance and disease relapse. Here, we report a Ph+B-ALL case with persistent minimal residual disease (MRD) after treatment with dasatinib. The patient expressed the P190BCR-ABL1 isoform and a novel BCR-ABL1 mutation, p.Y440C. The latter is in the C-terminal lobe of the kinase domain, which likely induces deviations in the protein structure and activity and destabilizes its inactive conformation. The treatment was substituted by bosutinib, which binds to the active conformation of the protein, prior to allogeneic bone marrow transplant to overcome the lack of a complete response to dasatinib. These findings strengthen the importance of BCR-ABL1 mutational screening in Ph+ patients, particularly for those who do not achieve complete molecular remission.
- Novel FGFR1 Mutations in Kallmann Syndrome and Normosmic Idiopathic Hypogonadotropic Hypogonadism: Evidence for the Involvement of an Alternatively Spliced IsoformPublication . Gonçalves, C; Bastos, M; Pignatelli, D; Borges, T; Aragüés, JM; Fonseca, F; Pereira, B; Socorro, S; Lemos, MOBJECTIVE: To determine the prevalence of fibroblast growth factor receptor 1 (FGFR1) mutations and their predicted functional consequences in patients with idiopathic hypogonadotropic hypogonadism (IHH). DESIGN: Cross-sectional study. SETTING: Multicentric. PATIENT(S): Fifty unrelated patients with IHH (21 with Kallmann syndrome and 29 with normosmic IHH). INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): Patients were screened for mutations in FGFR1. The functional consequences of mutations were predicted by in silico structural and conservation analysis. RESULT(S): Heterozygous FGFR1 mutations were identified in six (12%) kindreds. These consisted of frameshift mutations (p.Pro33-Alafs*17 and p.Tyr654*) and missense mutations in the signal peptide (p.Trp4Cys), in the D1 extracellular domain (p.Ser96Cys) and in the cytoplasmic tyrosine kinase domain (p.Met719Val). A missense mutation was identified in the alternatively spliced exon 8A (p.Ala353Thr) that exclusively affects the D3 extracellular domain of FGFR1 isoform IIIb. Structure-based and sequence-based prediction methods and the absence of these variants in 200 normal controls were all consistent with a critical role for the mutations in the activity of the receptor. Oligogenic inheritance (FGFR1/CHD7/PROKR2) was found in one patient. CONCLUSION(S): Two FGFR1 isoforms, IIIb and IIIc, result from alternative splicing of exons 8A and 8B, respectively. Loss-of-function of isoform IIIc is a cause of IHH, whereas isoform IIIb is thought to be redundant. Ours is the first report of normosmic IHH associated with a mutation in the alternatively spliced exon 8A and suggests that this disorder can be caused by defects in either of the two alternatively spliced FGFR1 isoforms.
- Screening a Targeted Panel of Genes by Next-Generation Sequencing Improves Risk Stratification in Real World Patients with Acute Myeloid LeukemiaPublication . Matos, S; Bernardo, P; Esteves, S; Botelho de Sousa, A; Lemos, M; Ribeiro, P; Silva, M; Nunes, A; Lobato, J; Frade, MJ; Gomes da Silva, M; Chacim, S; Mariz, J; Esteves, G; Raposo, J; Espadana, A; Carda, J; Barbosa, P; Martins, V; Carmo-Fonseca, M; Desterro, JAlthough mutation profiling of defined genes is recommended for classification of acute myeloid leukemia (AML) patients, screening of targeted gene panels using next-generation sequencing (NGS) is not always routinely used as standard of care. The objective of this study was to prospectively assess whether extended molecular monitoring using NGS adds clinical value for risk assessment in real-world AML patients. We analyzed a cohort of 268 newly diagnosed AML patients. We compared the prognostic stratification of our study population according to the European LeukemiaNet recommendations, before and after the incorporation of the extended mutational profile information obtained by NGS. Without access to NGS data, 63 patients (23%) failed to be stratified into risk groups. After NGS data, only 27 patients (10%) failed risk stratification. Another 33 patients were re-classified as adverse-risk patients once the NGS data was incorporated. In total, access to NGS data refined risk assessment for 62 patients (23%). We further compared clinical outcomes with prognostic stratification, and observed unexpected outcomes associated with FLT3 mutations. In conclusion, this study demonstrates the prognostic utility of screening AML patients for multiple gene mutations by NGS and underscores the need for further studies to refine the current risk classification criteria.
- Síndrome Hemofagocítica: um Suspeito a ConsiderarPublication . Souto Moura, T; Simões, I; Lemos, M; Azevedo, L; Gerivaz, R; Fonseca, PA síndrome hemofagocítica é uma entidade rara e potencialmente fatal, caracterizada por uma activação descontrolada do sistema imunitário, manifestando-se através de sintomas e sinais clínicos e laboratoriais de inflamação sistémica extrema. Pela inespecificidade dos mesmos, o seu diagnóstico requer um elevado grau de suspeição para implementação de terapêutica adequada e atempada. Os autores apresentam o caso de um jovem de 19 anos, previamente saudável, com febre com três semanas de evolução, interpretada no contexto de infecção respiratória, que subitamente apresentou subida de transaminases e pancitopenia ligeira, exantema cutâneo e hepatoesplenomegália. Os valores elevados de ferritina e receptor solúvel da interleucina-2, bem como a presença de hemofagocitose na medula óssea vieram confirmar o diagnóstico de síndrome hemofagocítica. Após 4 semanas de corticoterapia com dexametasona, assistiu-se a resolução dos sintomas e normalização dos parâmetros laboratoriais.