BRUNA LUCHEZE FREIRE
Projetos de Pesquisa
Unidades Organizacionais
LIM/42 - Laboratório de Hormônios e Genética Molecular, Hospital das Clínicas, Faculdade de Medicina
4 resultados
Resultados de Busca
Agora exibindo 1 - 4 de 4
- Diagnostic yield of a multigene sequencing approach in children classified as idiopathic short stature(2022) ANDRADE, Nathalia Liberatoscioli Menezes; FUNARI, Mariana Ferreira de Assis; MALAQUIAS, Alexsandra Christianne; COLLETT-SOLBERG, Paulo Ferrez; GOMES, Nathalia L. R. A.; SCALCO, Renata; DANTAS, Naiara Castelo Branco; REZENDE, Raissa C.; TIBURCIO, Angelica M. F. P.; SOUZA, Micheline A. R.; FREIRE, Bruna L.; V, Ana C. Krepischi; LONGUI, Carlos Alberto; LERARIO, Antonio Marcondes; ARNHOLD, Ivo J. P.; JORGE, Alexander A. L.; VASQUES, Gabriela AndradeObjectiveMost children with short stature remain without an etiologic diagnosis after extensive clinical and laboratory evaluation and are classified as idiopathic short stature (ISS). This study aimed to determine the diagnostic yield of a multigene analysis in children classified as ISS. Design and methodsWe selected 102 children with ISS and performed the genetic analysis as part of the initial investigation. We developed customized targeted panel sequencing, including all genes already implicated in the isolated short-stature phenotype. Rare and deleterious single nucleotide or copy number variants were assessed by bioinformatic tools. ResultsWe identified 20 heterozygous pathogenic (P) or likely pathogenic (LP) genetic variants in 17 of 102 patients (diagnostic yield = 16.7%). Three patients had more than one P/LP genetic alteration. Most of the findings were in genes associated with the growth plate differentiation: IHH (n = 4), SHOX (n = 3), FGFR3 (n = 2), NPR2 (n = 2), ACAN (n = 2), and COL2A1 (n = 1) or involved in the RAS/MAPK pathway: NF1 (n = 2), PTPN11 (n = 1), CBL (n = 1), and BRAF (n = 1). None of these patients had clinical findings to guide a candidate gene approach. The diagnostic yield was higher among children with severe short stature (35% vs 12.2% for height SDS <= or > -3; P = 0.034). The genetic diagnosis had an impact on clinical management for four children. ConclusionA multigene sequencing approach can determine the genetic etiology of short stature in up to one in six children with ISS, removing the term idiopathic from their clinical classification.
- Growth Hormone insensitivity (Laron syndrome): Report of a new family and review of Brazilian patients(2019) VILLELA, Thais R.; FREIRE, Bruna L.; BRAGA, Nathalia T. P.; ARANTES, Rodrigo R.; FUNARI, Mariana F. A.; JORGE, Alexander A. L.; SILVA, Ivani N.Laron's syndrome (LS) is a rare genetic disorder characterized by insensitivity to growth hormone (GH). Up to the present time, over 70 mutations of GH receptor (GHR) gene have been identified leading to GH/insulin-like growth factor type 1 (IGF1) signaling pathway defect. The number of LS patients worldwide is unknown, as many are probably undiagnosed. We report two sibs from a consanguineous family from Minas Gerais, southeastern Brazil. The parents have three children. The older, a 4-years-old girl was 80.2 cm tall (-5.7 SDS height/age), and the youngest sister, aged 3 years, was 73.2 cm tall (-5.82 SDS height/age). Their clinical and biochemical features are typical of LS patients, such as high serum level of GH and low IGF1 concentrations. A homozygous c.1A>T nucleotide substitution in GHR exon 2 in the probands' samples was identified. Their parents and healthy sister are heterozygous for the same variant that abolishes the translation initiation codon of GHR. This mutation has not been reported in Brazilian patients and was previously associated with an LS phenotype in a single 29-year-old Spanish man. In addition to this case report, we summarize the main characteristics and molecular data of the 21 LS Brazilian patients who have been published to date.
- A thermosensitive PCNA allele underlies an ataxia- telangiectasia-like disorder(2023) MAGRINO, Joseph; MUNFORD, Veridiana; MARTINS, Davi Jardim; HOMMA, Thais K.; PAGE, Brendan; GAUBITZ, Christl; FREIRE, Bruna L.; LERARIO, Antonio M.; VILAR, Juliana Brandstetter; AMORIN, Antonio; LEAO, Emilia K. E.; KOK, Fernand; MENCK, Carlos F. M.; JORGE, Alexander A. L.; KELCH, Brian A.Proliferating cell nuclear antigen (PCNA) is a sliding clamp protein that coordinates DNA replication with various DNA maintenance events that are critical for human health. Recently, a hypomorphic homozygous serine to isoleucine (S228I) substitu-tion in PCNA was described to underlie a rare DNA repair dis-order known as PCNA-associated DNA repair disorder (PARD). PARD symptoms range from UV sensitivity, neurodegeneration, telangiectasia, and premature aging. We, and others, previously showed that the S228I variant changes the protein-binding pocket of PCNA to a conformation that impairs interactions with specific partners. Here, we report a second PCNA substitution (C148S) that also causes PARD. Unlike PCNA-S228I, PCNA-C148S has WT-like structure and affinity toward partners. In contrast, both disease-associated variants possess a thermostability defect. Furthermore, patient-derived cells homozygous for the C148S allele exhibit low levels of chromatin-bound PCNA and display temperature-dependent phenotypes. The stability defect of both PARD variants indicates that PCNA levels are likely an important driver of PARD disease. These results significantly advance our understanding of PARD and will likely stimulate additional work focused on clinical, diagnostic, and therapeutic aspects of this severe disease.
- Recurrent Copy Number Variants Associated with Syndromic Short Stature of Unknown Cause(2018) HOMMA, Thais K.; KREPISCHI, Ana C. V.; FURUYA, Tatiane K.; HONJO, Rachel S.; MALAQUIAS, Alexsandra C.; BERTOLA, Debora R.; COSTA, Silvia S.; CANTON, Ana P.; ROELA, Rosimeire A.; FREIRE, Bruna L.; KIM, Chong A.; ROSENBERG, Carla; JORGE, Alexander A. L.Background/Aims: Genetic imbalances are responsible for many cases of short stature of unknown etiology. This study aims to identify recurrent pathogenic copy number variants (CNVs) in patients with syndromic short stature of unknown cause. Methods: We selected 229 children with short stature and dysmorphic features, developmental delay, and/or intellectual disability, but without a recognized syndrome. All patients were evaluated by chromosomal microarray (array-based comparative genomic hybridization/single nucleotide polymorphism array). Additionally, we searched databases and previous studies to recover recurrent pathogenic CNVs associated with short stature. Results: We identified 32 pathogenic/probably pathogenic CNVs in 229 patients. By reviewing the literature, we selected 4 previous studies which evaluated CNVs in cohorts of patients with short stature. Taken together, there were 671 patients with short stature of unknown cause evaluated by chromosomal microarray. Pathogenic/probably pathogenic CNVs were identified in 87 patients (13%). Seven recurrent CNVs, 22q11.21, 15q26, 1p36.33, Xp22.33, 17p13.3, 1q21.1, 2q24.2, were observed. They are responsible for about 40% of all pathogenic/probably pathogenic genomic imbalances found in short stature patients of unknown cause. Conclusion: CNVs seem to play a significant role in patients with short stature. Chromosomal microarray should be used as a diagnostic tool for evaluation of growth disorders, especially for syndromic short stature of unknown cause. (C) 2017 S. Karger AG, Basel