VINICIUS NAHIME DE BRITO
Projetos de Pesquisa
Unidades Organizacionais
LIM/42 - Laboratório de Hormônios e Genética Molecular, Hospital das Clínicas, Faculdade de Medicina
6 resultados
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Agora exibindo 1 - 6 de 6
- High Frequency of MKRN3 Mutations in Male Central Precocious Puberty Previously Classified as Idiopathic(2017) BESSA, Danielle S.; MACEDO, Delanie B.; BRITO, Vinicius N.; FRANCA, Monica M.; MONTENEGRO, Luciana R.; CUNHA-SILVA, Marina; SILVEIRA, Leticia G.; HUMMEL, Tiago; BERGADA, Ignacio; BRASLAVSKY, Debora; ABREU, Ana Paula; DAUBER, Andrew; MENDONCA, Berenice B.; KAISER, Ursula B.; LATRONICO, Ana ClaudiaBackground/Aims: Recently, loss-of-function mutations in the MKRN3 gene have been implicated in the etiology of familial central precocious puberty (CPP) in both sexes. We aimed to analyze the frequency of MKRN3 mutations in boys with CPP and to compare the clinical and hormonal features of boys with and without MKRN3 mutations. Methods: This was a retrospective review of clinical, hormonal and genetic features of 20 male patients with idiopathic CPP evaluated at an academic medical center. The entire coding regions of MKRN3, KISS1 and KISS1R genes were sequenced. Results: We studied 20 boys from 17 families with CPP. All of them had normal brain magnetic resonance imaging. Eight boys from 5 families harbored four distinct heterozygous MKRN3 mutations predicted to be deleterious for protein function, p.Ala162Glyfs*14, p.Arg213Glyfs*73, p.Arg328Cys and p. Arg365Ser. One boy carried a previously described KISS1-activating mutation (p.Pro74Ser). The frequency of MKRN3 mutations among these boys with idiopathic CPP was significantly higher than previously reported female data (40 vs. 6.4%, respectively, p < 0.001). Boys with MKRN3 mutations had typical clinical and hormonal features of CPP. Notably, they had later pubertal onset than boys without MKRN3 abnormalities (median age 8.2 vs. 7.0 years, respectively, p = 0.033). Conclusion: We demonstrated a high frequency of MKRN3 mutations in boys with CPP, previously classified as idiopathic, suggesting the importance of genetic analysis in this group. The boys with CPP due to MKRN3 mutations had classical features of CPP, but with puberty initiation at a borderline age. (C) 2016 S. Karger AG, Basel
- Central Precocious Puberty Caused by a Heterozygous Deletion in the MKRN3 Promoter Region (vol 107, pg 127, 2018)(2018) MACEDO, D. B.; FRANCA, M. M.; MONTENEGRO, L. R.; CUNHA-SILVA, M.; BESSA, D. S.; ABREU, A. P.; KAISER, U. B.; MENDONCA, B. B.; JORGE, A. A. L.; BRITO, V. N.; LATRONICO, A. N.
- New Causes of Central Precocious Puberty: The Role of Genetic Factors(2014) MACEDO, Delanie Bulcao; BRITO, Vinicius Nahime; LATRONICO, Ana ClaudiaA pivotal event in the onset of puberty in humans is the reemergence of the pulsatile release of the gonadotropin-releasing hormone (GnRH) from hypothalamic neurons. Pathways governing GnRH ontogeny and physiology have been discovered by studying animal models and humans with reproductive disorders. Recent human studies implicated the activation of kisspeptin and its cognate receptor (KISS1 / KISS1R) and the inactivation of MKRN3 in the premature reactivation of GnRH secretion, causing central precocious puberty (CPP). MKRN3, an imprinted gene located on the long arm of chromosome 15, encodes makorin ring finger protein 3, which is involved in ubiquitination and cell signaling. The MKRN3 protein is derived only from RNA transcribed from the paternally inherited copy of the gene due to maternal imprinting. Currently, MKRN3 defects represent the most frequent known genetic cause of familial CPP. In this review, we explored the clinical, hormonal and genetic aspects of children with sporadic or familial CPP caused by mutations in the kisspeptin and MKRN3 systems, essential genetic factors for pubertal timing. (C) 2014 S. Karger AG, Basel
- Long-Term Outcomes of Patients with Central Precocious Puberty due to Hypothalamic Hamartoma after GnRHa Treatment: Anthropometric, Metabolic, and Reproductive Aspects(2018) RAMOS, Carolina O.; LATRONICO, Ana C.; CUKIER, Priscilla; MACEDO, Delanie B.; BESSA, Danielle S.; CUNHA-SILVA, Marina; ARNHOLD, Ivo J.; MENDONCA, Berenice B.; BRITO, Vinicius N.Background: Hypothalamic hamartoma (HH) represents the commonest cause of organic central precocious puberty (CPP). Follow-up of these patients in adulthood is scarce. Objective: To describe the anthropometric, metabolic, and reproductive parameters of patients with CPP due to HH before and after treatment with gonadotropin-releasing hormone analog (GnRHa). Methods: We performed a retrospective and cross-sectional study in a single tertiary center including 14 patients (7 females) with CPP due to HH. Results: The mean duration of GnRHa treatment was 7.7 +/- 2.4 years in boys and 7.9 +/- 2.1 years in girls. GnRHa treatment was interrupted at the mean chronological age (CA) of 12.1 +/- 1.1 years in boys and 10.7 +/- 0.5 years in girls. At the last visit, the mean CA of the male and female patients was 21.5 +/- 3.2 and 24 +/- 3.9 years, respectively. Eleven of the 14 patients reached normal final height (FH) (standard deviation score -0.6 +/- 0.9 for males and -0.6 +/- 0.5 for females), all of them within the target height (TH) range. The remaining 3 patients had predicted height within the TH range. The mean body mass index and the percentage of body fat mass was significantly higher in females, with a higher prevalence of metabolic disorders. All patients presented normal gonadal function in adulthood, and 3 males fathered a child. Conclusion: All patients with CPP due to HH reached normal FH or near-FH. A higher prevalence of overweight/obesity and hypercholes-terolemia was observed in the female patients. Finally, no reproductive disorder was identified in both sexes, indicating that HH per se has no deleterious effect on the gonadotropic axis in adulthood. (c) 2017 S. Karger AG, Basel
- Central Precocious Puberty Caused by a Heterozygous Deletion in the MKRN3 Promoter Region(2018) MACEDO, Delanie B.; FRANCA, Monica M.; MONTENEGRO, Luciana R.; CUNHA-SILVA, Marina; BESSA, Danielle S.; ABREU, Ana Paula; KAISER, Ursula B.; MENDONCA, Berenice B.; JORGE, Alexander A. L.; BRITO, Vinicius N.; LATRONICO, Ana ClaudiaContext: Loss-of-function mutations in the coding region of MKRN3, a maternally imprinted gene at chromosome 15q11.2, are a common cause of familial central precocious puberty (CPP). Whether MKRN3 alterations in regulatory regions can cause CPP has not been explored to date. We aimed to investigate potential pathogenic variants in the promoter region of MKRN3 in patients with idiopathic CPP. Patients/Methods: A cohort of 110 patients with idiopathic CPP was studied. Family history of precocious sexual development was present in 25%. Mutations in the coding region of MKRN3 were excluded in all patients. Genomic DNA was extracted from peripheral blood leukocytes, and 1,100 nucleotides (nt) of the 5'-regulatory region of MKRN3 were amplified and sequenced. Luciferase assays were performed in GT1-7 cells transiently transfected with plasmids containing mutated and wild-type MKRN3 promoter. Results: We identified a rare heterozygous 4-nt deletion (c.-150_-147delTCAG; -38 to -41 nt upstream to the transcription start site) in the proximal promoter region of MKRN3 in a girl with CPP. In silico analysis predicted that this deletion would lead to the loss of a binding site for a downstream responsive element antagonist modulator (DREAM), a potential transcription factor for MKRN3 and GNRH1 expression. Luciferase assays demonstrated a significant reduction of MKRN3 promoter activity in transfected cells with a c.-150_-147delTCAG construct plasmid in both homozygous and heterozygous states when compared with cells transfected with the corresponding wild-type MKRN3 promoter region. Conclusion: A rare genetic alteration in the regulatory region of MKRN3 causes CPP. (c) 2018 S. Karger AG, Basel
- Outcomes of Patients with Central Precocious Puberty Due to Loss-of-Function Mutations in theMKRN3Gene after Treatment with Gonadotropin-Releasing Hormone Analog(2020) RAMOS, Carolina de Oliveira; MACEDO, Delanie B.; CANTON, Ana Pinheiro M.; CUNHA-SILVA, Marina; ANTONINI, Sonir R. R.; STECCHINI, Monica Freire; SERAPHIM, Carlos Eduardo; RODRIGUES, Tania; MENDONCA, Berenice Bilharinho; LATRONICO, Ana Claudia; BRITO, Vinicius NahimeIntroduction:Loss-of-function mutation ofMKRN3represents the most frequent genetic cause of familial central precocious puberty (CPP). The outcomes of gonadotropin-releasing hormone analog (GnRHa) treatment in CPP patients withMKRN3defects are unknown.Objective:To describe the clinical and hormonal features of patients with CPP with or withoutMKRN3mutations after GnRHa treatment. Anthropometric, metabolic and reproductive parameters were evaluated.Patients and Methods:Twenty-nine female patients with CPP due to loss-of-function mutations in theMKRN3and 43 female patients with idiopathic CPP were included. Their medical records were retrospectively evaluated for clinical, laboratory, and imaging study, before, during, and after GnRHa treatment. All patients with idiopathic CPP and 11 patients with CPP due toMKRN3defects reached final height (FH).Results:At the diagnosis, there were no significant differences between clinical and laboratory features of patients with CPP with or withoutMKRN3mutations. A high prevalence of overweight and obesity was observed in patients with CPP with or withoutMKRN3mutations (47.3 and 50%, respectively), followed by a significant reduction after GnRHa treatment. No significant differences in the values of mean FH and target height were found between the 2 CPP groups after GnRHa treatment. Menarche occurred at the expected age in patients with or without CPP due toMKRN3mutations (11.5 +/- 1.3 and 12 +/- 0.6 years, respectively). The prevalence of polycystic ovarian syndrome was 9.1% in patients with CPP due toMKRN3mutations and 5.9% in those with idiopathic CPP.Conclusion:Anthropometric, metabolic, and reproductive outcomes after GnRHa treatment were comparable in CPP patients, with or withoutMKRN3mutations, suggesting the absence of deleterious effects ofMKRN3defects in young female adults' life.