VINICIUS NAHIME DE BRITO
Projetos de Pesquisa
Unidades Organizacionais
LIM/42 - Laboratório de Hormônios e Genética Molecular, Hospital das Clínicas, Faculdade de Medicina
13 resultados
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article Weight-adjusted neonatal 17OH-progesterone cutoff levels improve the efficiency of newborn screening for congenital adrenal hyperplasia(2011) HAYASHI, Giselle; FAURE, Claudia; BRONDI, Maria Fernanda; VALLEJOS, Carla; SOARES, Daiana; OLIVEIRA, Erica; BRITO, Vinicius N.; MENDONCA, Berenice B.; BACHEGA, Tania A. S. S.Objective: To evaluate weight-adjusted strategy for levels of neonatal-17OHP in order to improve newborn screening (NBS) efficiency. Subjects and methods: Blood samples collected between 2-7 days of age from 67,640 newborns were evaluated. When N17OHP levels were >= 20 ng/mL, and a second sample was requested. We retrospectively analyzed neonatal-17OHP levels measured by Auto DELFIA-B024-112 assay, grouped according to birth-weight: G1: < 1,500 g, G2: 1,501-2,000 g, G3: 2,000-2,500 g and G4: > 2,500 g. 17OHP cutoff values were determined for each group using the 97.5th, 99th, 99.5th and 99.8th percentiles. Results: 0.5% of newborns presented false-positive results using the cutoff level >= 20 ng/mL for all groups. Neonates of low birthweight made up 69% of this group. Seven full-term newborns presented congenital adrenal hyperplasia (CAH) and, except for one of them, 17OHP levels were > 120 ng/mL. Only the 99.8th percentile presented higher predictive positive value (2%), and lower rate of false-positives in all groups. Conclusions: We suggest the use of 99.8th percentile obtained by weight-adjusted N17OHP values of healthy newborns to reduce the rate of false-positive results in NBS. Arq Bras Endocrinol Metab. 2011;55(8):632-7- Gonadal response after a single-dose stimulation test with recombinant human chorionic gonadotropin (rhCG) in patients with isolated prepubertal cryptorchidism(2016) OLIVEIRA, Leticia Ribeiro; HOMMA, Thais Kataoka; WOLOSZYNEK, Renata Reis; BRITO, Vinicius Nahime; LONGUI, Carlos AlbertoBackground: The evaluation of prepubertal gonadal Leydig cells secretion requires gonadotropin stimulation. Urinary hCG (human chorionic gonadotropin) is currently unavailable in many countries, however, recombinant hCG (rhCG) can be used. Our aim was to evaluate rhCG-stimulated testicular hormones in a group of patients with cryptorchidism. Methods: We evaluated 31 prepubertal boys (age range, 0.75-9.0 years) presenting with unilateral (n = 24) or bilateral (n = 7) cryptorchidism. Patients with other genital abnormalities, previous use of hCG or testosterone or previous surgeries were excluded. Blood samples were obtained at baseline and 7 days after a single subcutaneous dose of rhCG (Ovidrel (R) 250 mcg) to measure the testosterone, DHT (dihydrotestosterone), AMH (anti-Mullerian hormone), and inhibin B levels. Results: rhCG stimulation significantly increased testosterone levels from 10 ng/dl to 247.8 +/- 135.8 ng/dl, increased DHT levels from 4.6 +/- 0.8 to 32.3 +/- 18.0 ng/dl, and increased the T/DHT ratio from 2.2 +/- 0.4 to 8.0 +/- 3.5. There was also a significant increase in inhibin B (from 105.8 +/- 65.2 to 132.4 +/- 56.1 pg/ml; p < 0.05) and AMH levels (from 109.4 +/- 52.6 to 152.9 +/- 65.2 ng/ml; p < 0.01) after the rhCG stimulation. Conclusions: In this cohort, hormonal responses can be elicited after the rhCG stimulation test, suggesting that rhCG is a promising stimulation test to replace the urinary hCG test during the evaluation of gonadal Leydig cells function. The clinical applicability and adequate performance of rhCG testing must be investigated in future studies.
- 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 ClaudiaObjective: 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.
- Successful Pregnancies After Adequate Hormonal Replacement in Patients With Combined Pituitary Hormone Deficiencies(2017) CORREA, Fernanda A.; BIANCHI, Paulo H. M.; FRANCA, Marcela M.; OTTO, Aline P.; RODRIGUES, Rodrigo J. M.; EJZENBERG, Dani; SERAFINI, Paulo C.; BARACAT, Edmundo Chada; FRANCISCO, Rossana P. V.; BRITO, Vinicius N.; ARNHOLD, Ivo J. P.; MENDONCA, Berenice B.; CARVALHO, Luciani R.Context: Women with hypopituitarism have lower pregnancy rates after ovulation induction. Associated pituitary hormone deficiencies might play a role in this poorer outcome. Objective: We evaluated fertility treatment and pregnancy outcomes in five women with childhoodonset combined pituitary hormone deficiencies (CPHD). Patients and Methods: Five women with CPHD were referred for fertility treatment after adequacy of hormone replacement was determined. Patients were subjected to controlled ovarian stimulation (COS) for timed intercourse, intrauterine insemination, or in vitro fertilization, according to the presence or absence of other infertility factors (male or tubal). Results: All women became pregnant. The number of COS attempts until pregnancy was achieved varied between 1 and 5. The duration of COS resulting in at least one dominant follicle varied between 9 and 28 days, and total gonadotropin consumed varied between 1200 and 3450 IU. Two patients with severely suppressed basal gonadotropin levels since an early age had a cancelled COS cycle. All pregnancies were singleton except one (monochorionic twin gestation). The gestational ages at birth ranged from 35 weeks to 39 weeks and 4 days; three patients underwent cesarean section, and two had vaginal deliveries. Only one newborn was small for gestational age (delivered at 35 weeks). Conclusion: Adequate hormonal replacement prior to ovarian stimulation resulted in successful pregnancies in patients with childhood-onset CPHD, indicating that hormone replacement, including growth hormone, is an important step prior to fertility treatments in these patients.
- Methylome profiling of healthy and central precocious puberty girls(2018) BESSA, Danielle S.; MASCHIETTO, Mariana; AYLWIN, Carlos Francisco; CANTON, Ana P. M.; BRITO, Vinicius N.; MACEDO, Delanie B.; CUNHA-SILVA, Marina; PALHARES, Heloisa M. C.; RESENDE, Elisabete A. M. R. de; BORGES, Maria de Fatima; MENDONCA, Berenice B.; NETCHINE, Irene; KREPISCHI, Ana C. V.; LOMNICZI, Alejandro; OJEDA, Sergio R.; LATRONICO, Ana ClaudiaBackgroundRecent studies demonstrated that changes in DNA methylation (DNAm) and inactivation of two imprinted genes (MKRN3 and DLK1) alter the onset of female puberty. We aimed to investigate the association of DNAm profiling with the timing of human puberty analyzing the genome-wide DNAm patterns of peripheral blood leukocytes from ten female patients with central precocious puberty (CPP) and 33 healthy girls (15 pre- and 18 post-pubertal). For this purpose, we performed comparisons between the groups: pre- versus post-pubertal, CPP versus pre-pubertal, and CPP versus post-pubertal.ResultsAnalyzing the methylome changes associated with normal puberty, we identified 120 differentially methylated regions (DMRs) when comparing pre- and post-pubertal healthy girls. Most of these DMRs were hypermethylated in the pubertal group (99%) and located on the X chromosome (74%). Only one genomic region, containing the promoter of ZFP57, was hypomethylated in the pubertal group. ZFP57 is a transcriptional repressor required for both methylation and imprinting of multiple genomic loci. ZFP57 expression in the hypothalamus of female rhesus monkeys increased during peripubertal development, suggesting enhanced repression of downstream ZFP57 target genes. Fourteen other zinc finger (ZNF) genes were related to the hypermethylated DMRs at normal puberty. Analyzing the methylome changes associated with CPP, we demonstrated that the patients with CPP exhibited more hypermethylated CpG sites compared to both pre-pubertal (81%) and pubertal (89%) controls. Forty-eight ZNF genes were identified as having hypermethylated CpG sites in CPP.ConclusionMethylome profiling of girls at normal and precocious puberty revealed a widespread pattern of DNA hypermethylation, indicating that the pubertal process in humans is associated with specific changes in epigenetically driven regulatory control. Moreover, changes in methylation of several ZNF genes appear to be a distinct epigenetic modification underlying the initiation of human puberty.
- Applicability of a novel mathematical model for the prediction of adult height and age at menarche in girls with idiopathic central precocious puberty(2018) LOPES, Mateus Cavarzan; RAMOS, Carolina Oliveira; LATRONICO, Ana Claudia; MENDONCA, Berenice B.; BRITO, Vinicius N.OBJECTIVES: Unfavorable predicted adult height and psychosocial inadequacy represent parameters used to guide therapeutic intervention in girls with central precocious puberty. Gonadotropin-releasing hormone analog is the first-line treatment. The aim of this study was to compare two methods used to predict adult height and assess a validated tool for predicting the age at menarche in girls with central precocious puberty. METHODS: The predicted adult height of 48 girls with central precocious puberty was calculated at diagnosis using the Bayley-Pinneau method based on average and advanced bone age tables and compared with the predicted adult height calculated using a mathematical model. In addition, the age at spontaneous menarche was predicted using the new formulae. After Gonadotropin-releasing hormone analog treatment, the predicted adult height was calculated using only the Bayley-Pinneau tables. RESULTS: The achieved adult height was within the target height range in all treated girls with central precocious puberty. At diagnosis, the predicted adult height using the Bayley-Pinneau tables was lower than that using the mathematical model. After the Gonadotropin-releasing hormone analog treatment, the predicted adult height using the Bayley-Pinneau method with the average bone age tables was the closest to the achieved adult height. Using the formulae, the predicted age at spontaneous menarche was 10.1 +/- 0.5 yr. The Gonadotropin-releasing hormone analog treatment significantly postponed this event until 11.9 +/- 0.7 yr in these ""idiopathic"" central precocious puberty girls, highlighting the beneficial effect of this treatment. CONCLUSION: Both initial adult height prediction methods are limited and must be used with caution. The prediction of the age at spontaneous menarche represents an innovative tool that can help in clinical decisions regarding pubertal suppression.
- FGFR1 and PROKR2 rare variants found in patients with combined pituitary hormone deficiencies(2015) CORREA, Fernanda A.; TRARBACH, Ericka B.; TUSSET, Cintia; LATRONICO, Ana Claudia; MONTENEGRO, Luciana R.; CARVALHO, Luciani R.; FRANCA, Marcela M.; OTTO, Aline P.; COSTALONGA, Everlayny F.; BRITO, Vinicius N.; ABREU, Ana Paula; NISHI, Mirian Y.; JORGE, Alexander A. L.; ARNHOLD, Ivo J. P.; SIDIS, Yisrael; PITTELOUD, Nelly; MENDONCA, Berenice B.The genetic aetiology of congenital hypopituitarism (CH) is not entirely elucidated. FGFR1 and PROKR2 loss-of-function mutations are classically involved in hypogonadotrophic hypogonadism (HH), however, due to the clinical and genetic overlap of HH and CH; these genes may also be involved in the pathogenesis of CH. Using a candidate gene approach, we screened 156 Brazilian patients with combined pituitary hormone deficiencies (CPHD) for loss-of-function mutations in FGFR1 and PROKR2. We identified three FGFR1 variants (p.Arg448Trp, p.Ser107Leu and p.Pro772Ser) in four unrelated patients (two males) and two PROKR2 variants (p. Arg85Cys and p. Arg248Glu) in two unrelated female patients. Five of the six patients harbouring the variants had a first-degree relative that was an unaffected carrier of it. Results of functional studies indicated that the new FGFR1 variant p.Arg448Trp is a loss-of-function variant, while p.Ser107Leu and p.Pro772Ser present signalling activity similar to the wild-type form. Regarding PROKR2 variants, results from previous functional studies indicated that p.Arg85Cys moderately compromises receptor signalling through both MAPK and Ca2+ pathways while p.Arg248Glu decreases calcium mobilization but has normal MAPK activity. The presence of loss-of-function variants of FGFR1 and PROKR2 in our patients with CPHD is indicative of an adjuvant and/or modifier effect of these rare variants on the phenotype. The presence of the same variants in unaffected relatives implies that they cannot solely cause the phenotype. Other associated genetic and/or environmental modifiers may play a role in the aetiology of this condition.
- Pioneering studies on monogenic central precocious puberty(2019) CANTON, Ana Pinheiro Machado; SERAPHIM, Carlos Eduardo; BRITO, Vinicius Nahime; LATRONICO, Ana ClaudiaPubertal timing in humans is determined by complex interactions including hormonal, metabolic, environmental, ethnic, and genetic factors. Central precocious puberty (CPP) is defined as the premature reactivation of the hypothalamic-pituitary-gonadal axis, starting before the ages of 8 and 9 years in girls and boys, respectively; familial CPP is defined by the occurrence of CPP in two or more family members. Pioneering studies have evidenced the participation of genetic factors in pubertal timing, mainly identifying genetic causes of CPP in sporadic and familial cases. In this context, rare activating mutations were identified in genes of the kisspeptin excitatory pathway (KISS1R and KISS1 mutations). More recently, loss-of-function mutations in two imprinted genes (MKRN3 and DLK1) have been identified as important causes of familial CPP, describing novel players in the modulation of the hypothalamic-pituitary-gonadal axis in physiological and pathological conditions. MKRN3 mutations are the most common cause of familial CPP, and patients with MKRN3 mutations present clinical features indistinguishable from idiopathic CPP. Meanwhile, adult patients with DLK1 mutations present high frequency of metabolic alterations (overweight/obesity, early onset type 2 diabetes and hyperlipidemia), indicating that DLK1 may be a novel link between reproduction and metabolism.
- Sexuality and fertility desire in a large cohort of individuals with 46, XY differences in sex development(2023) BATISTA, Rafael Loch; INACIO, Marlene; BRITO, Vinicius Nahime; SIRCILI, Maria Helena Palma; BAG, Min Jeong; GOMES, Nathalia Lisboa; COSTA, Elaine Maria Frade; DOMENICE, Sorahia; MENDONCA, Berenice BilharinhoObjective: To analyze aspects of sexual life and fertility desire among 46, XY DSD people, including those who changed their gender. Methods: It is a cross-sectional study including 127 adults (> 16 years of age) with 46, XY DSD (83 females; 44 males) from a Single Brazilian Tertiary-Care Medical Center. Results: Sexual fantasies and masturbation were more frequent in 46, XY DSD males, whereas orgasm and sexual life satisfaction were similar in both genders. More 46, XY DSD men than women had a long-term romantic relationship. 46, XY DSD women with prenatal androgen exposure reported more fear of being romantically rejected. External genitalia appearance at birth did not impact the sexuality of 46, XY DSD women after surgical genital treatment had been completed. Overall, the sexual life was similar between 46, XY men assigned as males and those who changed to the male gender. Regarding sexual orientation, most self-reported as heterosexual (91% and 92% of women and men, respectively). The desire for fertility had a similar prevalence in both genders, but more women than men considered infertility a barrier to a long-term romantic relationship. Twelve individuals (7 males) had children; 10 out of 12 have adopted children. Conclusion: Fertility desire was shared among 46, XY DSD people, regardless of gender. Prenatal androgen exposure reduced the desire for motherhood in 46, XY women. 46, XY DSD people who changed from female to male gender presented similar sexual parameters as those assigned as males. Among females, virilized genitalia at birth did not affect sexuality once the surgical treatment is completed.
- Puberty: When is it normal?(2015) BRITO, Vinicius Nahime; LATRONICO, Ana Claudia