BACKGROUND The onset of puberty is first detected as an increase in pulsatile secretion of gonadotropin-releasing hormone (GnRH). Early activation of the hypothalamic–pituitary–gonadal axis results in central precocious puberty. The timing of pubertal development is driven in part by genetic factors, but only a few, rare molecular defects associated with central precocious puberty have been identified. METHODS We performed whole-exome sequencing in 40 members of 15 families with central precocious puberty. Candidate variants were confirmed with Sanger sequencing. We also performed quantitative real-time polymerase-chain-reaction assays to determine levels of messenger RNA (mRNA) in the hypothalami of mice at different ages. RESULTS We identified four novel heterozygous mutations in MKRN3, the gene encoding makorin RING-finger protein 3, in 5 of the 15 families; both sexes were affected. The mutations included three frameshift mutations, predicted to encode truncated proteins, and one missense mutation, predicted to disrupt protein function. MKRN3 is a paternally expressed, imprinted gene located in the Prader–Willi syndrome critical region (chromosome 15q11–q13). All affected persons inherited the mutations from their fathers, a finding that indicates perfect segregation with the mode of inheritance expected for an imprinted gene. Levels of Mkrn3 mRNA were high in the arcuate nucleus of prepubertal mice, decreased immediately before puberty, and remained low after puberty. CONCLUSIONS Deficiency of MKRN3 causes central precocious puberty in humans. (Funded by the National Institutes of Health and others.)

The genetic signature in this cohort was remarkably different than that observed in adults. Although observed at a lower prevalence, the spectrum of mutations was quite similar to that described in radiation-exposed pediatric PTCs. As mutations were unidentifiable in over 40% of the PTC cases, more comprehensive studies conducted in these patients will help to decipher the genetic landscape of sporadic pediatric PTCs.

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P450c17 deficiency is an autosomal recessive disorder and a rare cause of congenital adrenal hyperplasia characterized by hypertension, hypokalemia, and impaired production of sex hormones. We performed a clinical, hormonal, and molecular study of 11 patients from 6 Brazilian families with the combined 17alpha-hydroxylase/17,20-lyase deficiency phenotype. All patients had elevated basal serum levels of progesterone (1.8-38 ng/ml; 0.57-12 pmol/liter) and suppressed plasma renin activity. CYP17 genotyping identified 5 missense mutations. The compound heterozygous mutation R362C/W406R was found in 1 family, whereas the homozygous mutations R96W, Y329D, and P428L were seen in the other 5 families. The R96W mutation has been described as the cause of p450c17 deficiency in Caucasian patients. The other mutations were not found in 50 normal subjects screened by allele-specific oligonucleotide hybridization (Y329D, R362C, and W406R) or digestion with HphI (P428L) and were recently found in other Brazilian patients. Therefore, we elucidated the genotype of 11 individuals with p450c17 deficiency and concluded that basal progesterone measurement is a useful marker of p450c17 deficiency and that its use should reduce the misdiagnosis of this deficiency in patients presenting with male pseudohermaphroditism, primary or secondary amenorrhea, and mineralocorticoid excess syndrome.

Glucocorticoid therapy is pivotal in the treatment of acute lymphoblastic leukemia (ALL); it reduces cell proliferation, promotes cell cycle arrest, and induces cell death by apoptosis. The sensitivity of leukemic cells to glucocorticoids was previously related to the cell concentration of 3[H]dexamethasone-binding sites. The latter represents the classic glucocorticoid receptor (GR) isoform alpha that binds ligand and modulates the transcription rates of glucocorticoid-responsive genes. In ALL, lymphoblasts of T-lineage are less sensitive to glucocorticoids than cells of the B-lineage. The alternatively spliced GR isoform (GRP), which exerts a dominant negative effect on GRalpha-mediated transcriptional activity, has been proposed as a possible mediator of glucocorticoid resistance. In this study, we determined the amount of GRalpha and GRbeta in mononuclear cells from 13 newly diagnosed and untreated children with ALL and 9 controls by quantitative Western analysis. Generally, leukemic patients expressed 6 times less GRalpha (ALL= 0.54 +/- 1.1; controls = 3.1 +/- 0.9; p < 0.01) than controls, but the same amount of GRbeta (ALL=3.62 +/- 3.3; controls = 3.6 +/- 3.4). ALL patients with T-cell disease had a much lower GRalpha (0.09 +/- 0.1; p < 0.01) but a similar or slightly higher GRbeta (5.98 +/- 3.9; p = 0.1) expression than controls, with a GRalpha/GRbeta ratio 15 times smaller than controls. Mononuclear leukocytes of T-cell lineage expressed significantly lower GRalpha (p = 0.04) and higher GRbeta (p < 0.01) than cells of the pre-B immunophenotype, with a 10 times smaller ratio. We conclude that the combination of low GRalpha and normal-to-high GRbeta expression in leukemic lymphoblasts might represent one of the mechanisms responsible for their reduced glucocorticoid sensitivity; this is more pronounced in T-lineage cells.

Ressaltar os principais efeitos indesejáveis durante a corticoterapia, o mecanismo de seu desencadeamento e as medidas necessárias para minimizar os efeitos colaterais. Fontes dos dados: Experiência do autor, complementada com trabalhos publicados no MEDLINE. Síntese dos dados: Os princípios para que se minimizem os efeitos indesejáveis da corticoterapia incluem: a) indicação rígida em que o uso do glicocorticóide seja essencial; b) evitar o uso de glicocorticóides de ação prolongada, preferindo glicocorticóide de ação curta ou intermediária; c) reduzir ao mínimo necessário a duração do tratamento, visto que tratamentos com duração entre 5 e 7 dias apresentam poucos efeitos colaterais e rápida recuperação do eixo hipotalâmico-hipofisário; d) preferir glicocorticóides de ação local, como glicocorticóides inalatórios; e) associação com outros fármacos, em especial outros antiinflamatórios ou imunossupressores mais específicos, buscando efeitos sinérgicos que permitam evitar o uso de glicocorticóides ou reduzir a dose e o tempo da corticoterapia; f) oferecer a menor dose necessária para o efeito desejado, respeitando a sensibilidade de cada indivíduo aos glicocorticóides. Conclusões: o conhecimento das características farmacológicas e ações biológicas dos glicocorticóides permite a melhor opção terapêutica quanto à indicação, dose, via de administração e duração da corticoterapia.

Purpose: The purpose of this study was to verify the correlation between neck circumference (NC) and body mass index (BMI) in children, and to determine NC percentiles for Brazilian children. Methods: The subjects of this cross-sectional study were students between the ages of 6 and 19 years from five schools in São Paulo, Brazil. Clinical and anthropometric data were collected from the students from April 2011 to June 2012. NC was measured at the level of the cricoid cartilage. We calculated Pearson correlation coefficients between NC and other indices of obesity with Sigma Stat 3.5. NC percentiles were produced using the LMS (lambda, mu, and sigma) method (STATA 12.0). Results: Among 2,794 students, 49.9% were male. NC was significantly correlated with age, BMI, waist circumference (WC), and body fat percentage (%BF). The NC of boys was greater than that of girls. The NC curves of smoothed 3rd, 10th, 25th, 50th, 75th, 90th, and 97th percentiles were constructed by age and sex. Conclusions: NC can be used in the assessment of obesity in childhood. There was a positive correlation between NC and BMI, WC and %BF. This study was the first to provide NC percentiles for children in Brazil.

We observed great variability in the degree of external genitalia virilization in both CYP21A2 genotypes, and we showed that the CAG repeats of the androgen receptor gene influences this phenotypic variability.