LETICIA FERREIRA GONTIJO SILVEIRA

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LIM/42 - Laboratório de Hormônios e Genética Molecular, Hospital das Clínicas, Faculdade de Medicina

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Agora exibindo 1 - 10 de 29
  • article 17 Citação(ões) na Scopus
    Kisspeptin and Clinical Disorders
    (2013) SILVEIRA, Leticia Gontijo; LATRONICO, Ana Claudia; SEMINARA, Stephanie Beth
    The hypothalamic hormone GnRH has traditionally been viewed as a central driver of the hypothalamic-pituitary-gonadal axis. Pulsatile GnRH release is required for pulsatile gonadotropin secretion, which then modulates gonadal steroid feedback and brings about full fertility in the adult. Pathways governing GnRH ontogeny and physiology have been discovered by studying humans with disorders of GnRH secretion. In this chapter, the human genetics of the kisspeptin signaling pathway in patients with diverse reproductive phenotypes will be explored. The discovery of defects in the kisspeptin system in several reproductive disorders has shed light on the mechanisms involved in regulating GnRH secretion, revealing the critical role played by the kisspeptin signaling pathway in pubertal initiation and reproductive function.
  • article 42 Citação(ões) na Scopus
    Mutational analysis of TAC3 and TACR3 genes in patients with idiopathic central pubertal disorders
    (2012) TUSSET, Cintia; NOEL, Sekoni D.; TRARBACH, Ericka B.; SILVEIRA, Leticia F. G.; JORGE, Alexander A. L.; BRITO, Vinicius N.; CUKIER, Priscila; SEMINARA, Stephanie B.; MENDONCA, Berenice B. de; KAISER, Ursula B.; LATRONICO, Ana Claudia
    Objective: To investigate the presence of variants in the TAC3 and TACR3 genes, which encode NKB and its receptor (NK3R), respectively, in a large cohort of patients with idiopathic central pubertal disorders. Subjects and methods: Two hundred and thirty seven patients were studied: 114 with central precocious puberty (CPP), 73 with normosmic isolated hypogonadotropic hypogonadism (IHH), and 50 with constitutional delay of growth and puberty (CDGP). The control group consisted of 150 Brazilian individuals with normal pubertal development. Genomic DNA was extracted from peripheral blood and the entire coding region of both TAC3 and TACR3 genes were amplified and automatically sequenced. Results: We identified one variant (p.A63P) in NKB and four variants, p.G18D, p.L58L (c.172C > T), p.W275* and p.A449S in NK3R, which were absent in the control group. The p.A63P variant was identified in a girl with CPP, and p.A449S in a girl with CDGP. The known p.G18D, p.L58L, and p.W275* variants were identified in three unrelated males with normosmic IHH. Conclusion: Rare variants in the TAC3 and TACR3 genes were identified in patients with central pubertal disorders. Loss-of-function variants of TACR3 were associated with the normosmic IHH phenotype.
  • conferenceObject
    Apparently Sporadic Central Precocious Puberty Is Caused By Paternally Inherited Mutations in the Imprinted MKRN3 Gene
    (2014) ABREU, Ana Paula; MACEDO, Delanie B.; REIS, Ana Claudia Silva; MONTENEGRO, Luciana Ribeiro; DAUBER, Andrew; BENEDUZZI, Diane; CULIER, Priscilla; SILVEIRA, Leticia Gontijo; TELES, Milena Gurgel; CARROLL, Rona S.; GUERRA, Gil; GUARAGNA FILHO, Guilherme; GUCEV, Zoran Spasico; ARNHOLD, Ivo J. P.; CASTRO, Margaret; MOREIRA, Ayrton Custodio; MARTINELLI, Carlos Eduardo; HIRSCHHORN, Joel N.; MENDONASA, Berenice Bilharinho; BRITO, Vinicius N.; ANTONINI, Sonir Roberto; KAISER, Ursula B.; LATRONICO, Ana Claudia
  • article 59 Citação(ões) na Scopus
    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 Claudia
    Background/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
  • bookPart 0 Citação(ões) na Scopus
    Benefits and adverses effects of testosterone therapy
    (2017) COSTA, E. M. F.; AMATO, L. G. L.; SILVEIRA, L. F. G.
    Testosterone plays an essential role in several aspects of men’s health. The main indication for testosterone treatment is in men with a confirmed diagnosis of hypogonadism, signs of androgen deficiency, and low serum testosterone levels. Other possible indications include constitutional delay of growth and puberty, men with sexual dysfunction, female to male transgender persons, androgen deficiency in the aging male, hypogonadism secondary to drugs, and chronic illness. Common drug-related adverse events include increase in hematocrit, acne, breast tenderness, gynecomastia, and exogenous testosterone can lead to a state of transitory infertility. It is not recommended to begin testosterone replacement therapy in men with untreated severe obstructive sleep apnea or with benign prostatic hypertrophy. The effects of testosterone on lipid metabolism and cardiovascular risk remain uncertain. In each situation the testosterone replacement brings specific benefits but the overall goals of therapy are to establish and maintain secondary sexual characteristics, sexual function, sense of well-being, and to improve body composition, muscle mass and strength, bone mineral density, and quality of life. © Springer International Publishing Switzerland 2017.
  • article 7 Citação(ões) na Scopus
    Association between KISS1 rs5780218 promoter polymorphism and onset of growth hormone secreting pituitary adenoma
    (2019) AMORIM, Paulo V. G. H.; GRANDE, Isabella P. P.; BATISTA, Rafael L.; SILVEIRA, Leticia F. G.; FREIRE, Ane Caroline T. B.; BRONSTEIN, Marcello D.; JALLAD, Raquel S.; TRARBACH, Ericka B.
    Objectives. - This study analyzed the KISS1 c.-145delA (rs5780218) promoter polymorphism in a cohort of patients with growth hormone secreting pituitary adenoma (somatotropinoma) and controls, to investigate its role in the incidence of acromegaly and to assess patient/tumor characteristics. Material and methods rs5780218 allelic and genotypic distributions were compared between 49 somatotropinoma patients and 167 healthy controls. rs5780218 was also assessed in relation to patient characteristics and tumor aggressiveness, as characterized by tumor invasion and resistance to conventional therapy. The relationship between KISS1 mRNA expression and the rs5780218 genotype was also assessed in available pituitary tumor samples. Results. - The homozygous -/- variant genotype was associated with high rates of somatotropinoma (P < 0.01), but not with tumor invasiveness, patient characteristics or hormonal remission. KISS1 mRNA expression was much lower in somatotropinomas carrying the deleted allele than in homozygous wild type AA. Conclusions. - In this pilot study, the rs5780218 promoter polymorphism was evaluated in pituitary adenoma, and showed a possible association with the incidence of somatotropinoma but not with tumor progression.
  • article 8 Citação(ões) na Scopus
    Clinical and molecular aspects of congenital isolated hypogonadotropic hypogonadism
    (2011) TUSSET, Cintia; TRARBACH, Ericka B.; SILVEIRA, Leticia Ferreira Gontijo; BENEDUZZI, Daiane; MONTENEGRO, Luciana; LATRONICO, Ana Claudia
    Congenital isolated hypogonadotropic hypogonadism (IHH) is characterized by partial or complete lack of pubertal development due to defects in migration, synthesis, secretion or action of gonadotropin-releasing hormone (GnRH). Laboratory diagnosis is based on the presence of low levels of sex steroids, associated with low or inappropriately normal levels of pituitary gonadotropins (LH and FSH). Secretion of other pituitary hormones is normal, as well magnetic resonance imaging of the hypothalamohypophyseal tract, which shows absence of an anatomical defects. When IHH is associated with olfactory abnormalities (anosmia or hyposmia), it characterizes Kallmann syndrome. A growing list of genes is involved in the etiology of IHH, suggesting the heterogeneity and complexity of the genetic bases of this condition. Defects in olfactory and GnRH neuron migration are the etiopathogenic basis of Kallmann syndrome. Mutations in KAL1, FGFR1/FGF8, PROK2/PROKR2, NELF, CHD7, HS6ST1 and WDR11 are associated with defects in neuronal migration, leading to Kallmann syndrome. Notably, defects in FGFR1, FGF8, PROKR2, CHD7 and WDR11 are also associated with IHH, without olfactory abnormalities (normosmic IHH), although in a lower frequency. Mutations in KISS1R, TAC3/TACR3 and GNRH1/GNRHR are described exclusively in patients with normosmic IHH. In this paper, we reviewed the clinical, hormonal and genetic aspects of IHH. Arq Bras Endocrinol Metab. 2011;55(8):501-11
  • conferenceObject
    Prevalence of Micropenis in Isolated Congenital Hypogonadotropic Hypogonadism and Treatment Outcome after Testosterone Replacement Therapy
    (2015) LIMA, L.; FARIA, A.; COSTA, E.; LATRONICO, A.; MENDONCA, B.; GONTIJO, L.
  • article 19 Citação(ões) na Scopus
    Mutational analysis of KISS1 and KISS1R in idiopathic central precocious puberty
    (2014) KRSTEVSKA-KONSTANTINOVA, Marina; JOVANOVSKA, Jana; TASIC, Velibor B.; MONTENEGRO, Luciana Ribeiro; BENEDUZZI, Daiane; SILVEIRA, Leticia F. G.; GUCEV, Zoran S.
    Aim: The genetic background of idiopathic central precocious puberty (ICPP) is not well understood. The genetic activation of pubertal onset is thought to arise from the effect of multiple genes. Familial ICPP has been reported suggesting the existence of monogenic causes of ICPP. Kisspeptin and its receptor are found to be involved in gonadotropin-releasing hormone (GnRH) secretion and puberty onset. Mutations in their genes, KISS1 and KISSR, have been suggested to be causative for ICPP. Methods: ICPP was defined by pubertal onset before 8 years of age in girls, and a pubertal luteinizing hormone (LH) response to GnRH testing. Twenty-eight girls with ICPP were included in the study [age at diagnosis was 5.72 +/- 2.59, with a mean bone age advancement of 1.4 years (-0.1 to 2.8). Height at onset of therapy in SD score was 0.90 +/- 1.48 for age]. Luteinizing hormone-releasing hormone test was performed in all subjects, and all of them had a pubertal response (LH 20.35 +/- 32.37 mIU/mL; FSH 23.32 +/- 15.72 mIU/mL). The coding regions of KISS1 and KISS1R were sequenced. Results: No rare variants were detected in KISS1 or KISS1R in the 28 subjects with ICPP. Conclusions: We confirmed that mutations in KISS1 and KISS1R are not a common cause for ICPP. Conclusions: We confirmed that mutations in KISS1 and KISS1R are not a common cause for ICPP.
  • article 0 Citação(ões) na Scopus
    Nonsense Mutations in FGF8 Gene Causing Different Degrees of Human Gonadotropin-Releasing Deficiency (vol 95, pg 3491, 2010)
    (2011) TRARBACH, Ericka B.; ABREU, Ana Paula; FERREIRA, Leticia; SILVEIRA, Gontijo; GARMES, Heraldo Mendes; BAPTISTA, Maria TerezaM.; TELES, Milena Gurgel; COSTA, ElaineM. F.; MOHAMMADI, Moosa; PITTELOUD, Nelly; MENDONCA, Berenice B.; LATRONICO, Ana Claudia