VINICIUS NAHIME DE BRITO
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LIM/42 - Laboratório de Hormônios e Genética Molecular, Hospital das Clínicas, Faculdade de Medicina
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conferenceObject X-Linked Central Precocious Puberty Associated with MECP2 defects(2022) CANTON, Ana; TINANO, Flavia; GUASTI, Leonardo; MONTENEGRO, Luciana; RYAN, Fiona; SHEARS, Deborah; MELO, Maria Edna; GOMES, Larissa; PIANA, Mariana; BRAUNER, Raja; ESPINO, Rafael; ESCRIBANO-MUNOZ, Arancha; PAGANONI, Alyssa; KORBONITS, Marta; SERAPHIM, Carlos Eduardo; FARIA, Aline; COSTA, Silvia; KREPISCHI, Ana Cristina; JORGE, Alexander; DAVID, Alessia; ARGENTE, Jesus; MENDONCA, Berenice; BRITO, Vinicius; HOWARD, Sasha; LATRONICO, Ana Claudia- DLK1 Is a Novel Link Between Reproduction and Metabolism(2019) GAMES, Larissa G.; CUNHA-SILVA, Marina; CRESPO, Raiane P.; RAMOS, Carolina O.; MONTENEGRO, Luciana R.; CANTON, Ana; LEES, Melissa; SPOUDEAS, Helen; DAUBER, Andrew; MACEDO, Delanie B.; BESSA, Danielle S.; MACIEL, Gustavo A.; BARACAT, Edmund C.; JORGE, Alexander A. L.; MENDONCA, Berenice B.; BRITO, Vinicius N.; LATRONICO, Ana ClaudiaBackground: Delta-like homolog 1 (DLK1), also called preadipocyte factor 1, prevents adipocyte differentiation and has been considered a molecular gatekeeper of adipogenesis. A DLK1 complex genomic defect was identified in five women from a single family with central precocious puberty (CPP) and increased body fat percentage. Methods: We studied 60 female patients with a diagnosis of CPP or history of precocious menarche. Thirty-one of them reported a family history of precocious puberty. DLK1 DNA sequencing was performed in all patients. Serum DLK1 concentrations were measured using an ELISA assay in selected cases. Metabolic and reproductive profiles of adult women with CPP caused by DLK1 defects were compared with those of 20 women with idiopathic CPP. Results: We identified three frameshift mutations of DLK1 (p.Gly199Alafs*11, p.Va1271Cysfs*14, and p.Pro160Leufs*50) in five women from three families with CPP. Segregation analysis was consistent with the maternal imprinting of DLK1. Serum DLK1 concentrations were undetectable in three affected women. Metabolic abnormalities, such as overweight/obesity, early-onset glucose intolerance/type 2 diabetes mellitus, and hyperlipidemia, were more prevalent in women with the DLK1 mutation than in the idiopathic CPP group. Notably, the human metabolic alterations were similar to the previously described dlk1-null mice phenotype. Two sisters who carried the p.Gly199Alafs*11 mutation also exhibited polycystic ovary syndrome and infertility. Conclusions: Loss-of-function mutations of DLK1 are a definitive cause of familial CPP. The high prevalence of metabolic alterations in adult women who experienced CPP due to DLK1 defects suggests that this antiadipogenic factor represents a link between reproduction and metabolism.
- Insights from the genetic characterization of central precocious puberty associated with multiple anomalies(2021) CANTON, Ana Pinheiro Machado; KREPISCHI, Ana Cristina Victorino; MONTENEGRO, Luciana Ribeiro; COSTA, Silvia; ROSENBERG, Carla; STEUNOU, Virginie; SOBRIER, Marie-Laure; SANTANA, Lucas; HONJO, Rachel Sayuri; KIM, Chong Ae; ZEGHER, Francis de; IDKOWIAK, Jan; GILLIGAN, Lorna C.; ARLT, Wiebke; FUNARI, Mariana Ferreira de Assis; JORGE, Alexander Augusto de Lima; MENDONCA, Berenice Bilharinho; NETCHINE, Irene; BRITO, Vinicius Nahime; LATRONICO, Ana ClaudiaSTUDY QUESTION: Is there an (epi)genetic basis in patients with central precocious puberty (CPP) associated with multiple anomalies that unmasks underlying mechanisms or reveals novel genetic findings related to human pubertal control? SUMMARY ANSWER: In a group of 36 patients with CPP associated with multiple phenotypes, pathogenic or likely pathogenic (epi)genetic defects were identified in 12 (33%) patients, providing insights into the genetics of human pubertal control. WHAT IS KNOWN ALREADY: A few studies have described patients with CPP associated with multiple anomalies, but without making inferences on causalities of CPP. Genetic-molecular studies of syndromic cases may reveal disease genes or mechanisms, as the presentation of such patients likely indicates a genetic disorder. STUDY DESIGN, SIZE, DURATION: This translational study was based on a genetic-molecular analysis, including genome-wide high throughput methodologies, for searching structural or sequence variants implicated in CPP and DNA methylation analysis of candidate regions. PARTICIPANTS/MATERIALS, SETTING, METHODS: A cohort of 197 patients (188 girls) with CPP without structural brain lesions was submitted to a detailed clinical evaluation, allowing the selection of 36 unrelated patients (32 girls) with CPP associated with multiple anomalies. Pathogenic allelic variants of genes known to cause monogenic CPP (KISS1R, KISS1, MKRN3 and DLK1) had been excluded in the entire cohort (197 patients). All selected patients with CPP associated with multiple anomalies (n = 36) underwent methylation analysis of candidate regions and chromosomal microarray analysis. A subset (n = 9) underwent whole-exome sequencing, due to presenting familial CPP and/or severe congenital malformations and neurocognitive abnormalities. MAIN RESULTS AND THE ROLE OF CHANCE: Among the 36 selected patients with CPP, the more prevalent associated anomalies were metabolic, growth and neurocognitive conditions. In 12 (33%) of them, rare genetic abnormalities were identified: six patients presented genetic defects in loci known to be involved with CPP (14q32.2 and 7q11.23), whereas the other six presented defects in candidate genes or regions. In detail, three patients presented hypomethylation of DLK1/MEG3:IG-DMR (14q32.2 disruption or Temple syndrome), resulting from epimutation (n = 1) or maternal uniparental disomy of chromosome 14 (n = 2). Seven patients presented pathogenic copy number variants: three with de novo 7q11.23 deletions (Williams-Beuren syndrome), three with inherited Xp22.33 deletions, and one with de novo 1p31.3 duplication. Exome sequencing revealed potential pathogenic variants in two patients: a sporadic female case with frameshift variants in TNRC6B and AREL1 and a familial male case with a missense substitution in UGT2B4 and a frameshift deletion in MKKS. LIMITATIONS, REASONS FOR CAUTION: The selection of patients was based on a retrospective clinical characterization, lacking a longitudinal inclusion of consecutive patients. In addition, future studies are needed, showing the long-term (mainly reproductive) outcomes in the included patients, as most of them are not in adult life yet. WIDER IMPLICATIONS OF THE FINDINGS: The results highlighted the relevance of an integrative clinical-genetic approach in the elucidation of mechanisms and factors involved in pubertal control. Chromosome 14q32.2 disruption indicated the loss of imprinting of DLK1 as a probable mechanism of CPP. Two other chromosomal regions (7q11.23 and Xp22.33) represented new candidate loci potentially involved in this disorder of pubertal timing.
- Rare variants in the MECP2 gene in girls with central precocious puberty: a translational cohort study(2023) CANTON, Ana P. M.; TINANO, Flavia R.; GUASTI, Leonardo; MONTENEGRO, Luciana R.; RYAN, Fiona; SHEARS, Deborah; MELO, Maria Edna de; GOMES, Larissa G.; PIANA, Mariana P.; BRAUNER, Raja; ESPINO-AGUILAR, Rafael; ESCRIBANO-MUNOZ, Arancha; PAGANONI, Alyssa; READ, Jordan E.; KORBONITS, Marta; SERAPHIM, Carlos E.; COSTA, Silvia S.; KREPISCHI, Ana Cristina; JORGE, Alexander A. L.; DAVID, Alessia; KAISINGER, Lena R.; ONG, Ken K.; PERRY, John R. B.; ABREU, Ana Paula; KAISER, Ursula B.; ARGENTE, Jesus; MENDONCA, Berenice B.; BRITO, Vinicius N.; HOWARD, Sasha R.; LATRONICO, Ana ClaudiaBackground Identification of genetic causes of central precocious puberty have revealed epigenetic mechanisms as regulators of human pubertal timing. MECP2, an X-linked gene, encodes a chromatin-associated protein with a role in gene transcription. MECP2 loss-of-function mutations usually cause Rett syndrome, a severe neurodevelopmental disorder. Early pubertal development has been shown in several patients with Rett syndrome. The aim of this study was to explore whether MECP2 variants are associated with an idiopathic central precocious puberty phenotype. Methods In this translational cohort study, participants were recruited from seven tertiary centres from five countries (Brazil, Spain, France, the USA, and the UK). Patients with idiopathic central precocious puberty were investigated for rare potentially damaging variants in the MECP2 gene, to assess whether MECP2 might contribute to the cause of central precocious puberty. Inclusion criteria were the development of progressive pubertal signs (Tanner stage 2) before the age of 8 years in girls and 9 years in boys and basal or GnRH-stimulated LH pubertal concentrations. Exclusion criteria were the diagnosis of peripheral precocious puberty and the presence of any recognised cause of central precocious puberty (CNS lesions, known monogenic causes, genetic syndromes, or early exposure to sex steroids). All patients included were followed up at the outpatient clinics of participating academic centres. We used high-throughput sequencing in 133 patients and Sanger sequencing of MECP2 in an additional 271 patients. Hypothalamic expression of Mecp2 and colocalisation with GnRH neurons were determined in mice to show expression of Mecp2 in key nuclei related to pubertal timing regulation. Findings Between Jun 15, 2020, and Jun 15, 2022, 404 patients with idiopathic central precocious puberty (383 [95%] girls and 21 [5%] boys; 261 [65%] sporadic cases and 143 [35%] familial cases from 134 unrelated families) were enrolled and assessed. We identified three rare heterozygous likely damaging coding variants in MECP2 in five girls: a de novo missense variant (Arg97Cys) in two monozygotic twin sisters with central precocious puberty and microcephaly; a de novo missense variant (Ser176Arg) in one girl with sporadic central precocious puberty, obesity, and autism; and an insertion (Ala6_Ala8dup) in two unrelated girls with sporadic central precocious puberty. Additionally, we identified one rare heterozygous 3 & PRIME;UTR MECP2 insertion (36_37insT) in two unrelated girls with sporadic central precocious puberty. None of them manifested Rett syndrome. Mecp2 protein colocalised with GnRH expression in hypothalamic nuclei responsible for GnRH regulation in mice. Interpretation We identified rare MECP2 variants in girls with central precocious puberty, with or without mild neurodevelopmental abnormalities. MECP2 might have a role in the hypothalamic control of human pubertal timing, adding to the evidence of involvement of epigenetic and genetic mechanisms in this crucial biological process.