LETICIA FERREIRA GONTIJO SILVEIRA
Projetos de Pesquisa
Unidades Organizacionais
LIM/42 - Laboratório de Hormônios e Genética Molecular, Hospital das Clínicas, Faculdade de Medicina
6 resultados
Resultados de Busca
Agora exibindo 1 - 6 de 6
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.- 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.
- Absence of Functional LIN28B Mutations in a Large Cohort of Patients with Idiopathic Central Precocious Puberty(2012) SILVEIRA-NETO, Acacio P.; LEAL, Leticia Ferro; EMERMAN, Amy B.; HENDERSON, Katherine D.; PISKOUNOVA, Elena; HENDERSON, Brian E.; GREGORY, Richard I.; SILVEIRA, Leticia F. Gontijo; HIRSCHHORN, Joel N.; NGUYEN, Thutrang T.; BENEDUZZI, Daiane; TUSSET, Cintia; REIS, Ana Claudia S.; BRITO, Vinicius N.; MENDONCA, Berenice B.; PALMERT, Mark R.; ANTONINI, Sonir R.; LATRONICO, Ana ClaudiaAim: To investigate LIN28B gene variants in children with idiopathic central precocious puberty (CPP). Patients and Methods: We studied 178 Brazilian children with CPP (171 girls, 16.8% familial cases). A large multiethnic group (1,599 subjects; Multiethnic Cohort, MEC) was used as control. DNA analysis and biochemical in vitro studies were performed. Results: A heterozygous LIN28B variant, p. H199R, was identified in a girl who developed CPP at 5.2 years. This variant was absent in 310 Brazilian control individuals, but it was found in the same allele frequency in women from the MEC cohort, independent of the age of menarche. Functional studies revealed that when ectopically expressed in cells, the mutant protein was capable of binding pre-let-7 microRNA and inhibiting let-7 expression to the same extent as wild-type Lin28B protein. Other rare LIN28B variants (p.P173P, c.198+32_33delCT, g.9575731A>C and c.-11C>T) were identified in CPP patients and controls. Therefore, no functional mutation was identified. Conclusion: In vitro studies revealed that the rare LIN28B p.H199R variant identified in a girl with CPP does not affect the Lin28B function in the regulation of let-7 expression. Although LIN28B SNPs were associated with normal pubertal timing, rare variations in this gene do not seem to be commonly involved in the molecular pathogenesis of CPP.
- Molecular and Gene Network Analysis of Thyroid Transcription Factor 1 (TTF1) and Enhanced at Puberty (EAP1) Genes in Patients with GnRH-Dependent Pubertal Disorders(2013) CUKIER, Priscilla; WRIGHT, Hollis; RULFS, Tomke; SILVEIRA, Leticia Ferreira Gontijo; TELES, Milena Gurgel; MENDONCA, Berenice Bilharinho; ARNHOLD, Ivo J. P.; HEGER, Sabine; LATRONICO, Ana Claudia; OJEDA, Sergio R.; BRITO, Vinicius NahimeBackground/Aim: TTF1 and EAP1 are transcription factors that modulate gonadotropin-releasing hormone expression. We investigated the contribution of TTF1 and EAP1 genes to central pubertal disorders. Patients and Methods: 133 patients with central pubertal disorders were studied: 86 with central precocious puberty and 47 with normosmic isolated hypogonadotropic hypogonadism. The coding region of TTF1 and EAP1 were sequenced. Variations of polyglutamine and polyalanine repeats in EAP1 were analyzed by GeneScan software. Association of TTF1 and EAP1 to genes implicated in timing of puberty was investigated by meta-network framework GeneMANIA and Cytoscape software. Results: Direct sequencing of the TTF1 did not reveal any mutation or polymorphisms. Four EAP1 synonymous variants were identified with similar frequencies among groups. The most common EAP1 5'-distal polyalanine genotype was the homozygous 12/12, but the genotype 12/9 was identified in 2 central precocious puberty sisters without functional alteration in EAP1 transcriptional activity. TTF1 and EAP1 were connected, via genetic networks, to genes implicated in the control of menarche. Conclusion: No TTF1 or EAP1 germline mutations were associated with central pubertal disorders. TTF1 and EAP1 may affect puberty by changing expression in response to other members of puberty-associated gene networks, or by differentially affecting the expression of gene components of these networks. (C) 2013 S. Karger AG, Basel
conferenceObject Clinical Presentation of Klinefelter Syndrome and Other Causes of Hypergonadotropic Hypogonadism(2016) SCHNOLL, C.; RENCK, A. Covallero; LIMA, L. Guimaraes; MENDONCA, B. Bilharinho de; LATRONICO, A. C.; SILVEIRA, L. F. G.conferenceObject A New GNRH1 Mutation in a Boy with Congenital Isolated Hypogonadotropic Hypogonadism(2016) LIMA, L. Guimaraes; MONTENEGRO, L. Ribeiro; LERARIO, A. Marcondes; NISHI, M.; MENDONCA, B. B.; LATRONICO, A. C.; SILVEIRA, L. Ferreira Gontijo