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SUMMARY Beckwith-Wiedemann syndrome (BWS) is a common genetic congenital disease characterized by somatic overgrowth and its broad clinical spectrum includes pre- and post-natal macrosomia, macroglossia, visceromegaly, increased risk of neonatal hypoglycemia, and development of embryonic tumors. BWS occurs due to genetic/epigenetic changes involving growth-regulating genes, located on region 11p15, with an important genotype-phenotype correlation. Congenital adrenal hyperplasia (CAH) comprises a spectrum of autosomal recessive diseases presenting a variety of clinical manifestations due to a deficiency in one of the enzymes involved in cortisol secretion. Early diagnosis based on newborn screening prevents the adrenal crisis and early infant death. However, high 17-hydroxyprogesterone (17-OHP) levels can occur in newborns or premature infants without CAH, in situations of stress due to maternal or neonatal factors. Here, we report new cases of false-positive diagnosis of 21-hydroxylase deficiency during newborn screening - two girls and one boy with BWS. Methylation-specific multiplex ligation-dependent probe amplification revealed a gain of methylation in the H19 differentially methylated region. Notably, all three cases showed a complete normalization of biochemical changes, highlighting the transient nature of these hormonal findings that imitate the classical form of CAH. This report sheds light on a new cause of false-positive 21-hydroxylase deficiency diagnosis during newborn screening: Beckwith-Wiedemann syndrome.
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ABSTRACT Congenital adrenal hyperplasia due to 21-hydroxylase deficiency is an autosomal recessive disorder caused by CYP21A2 gene mutations, and its molecular diagnosis is widely used in clinical practice to confirm the hormonal diagnosis. Hence, considering the miscegenation of the Brazilian population, it is important to determine a mutations panel to optimise the molecular diagnosis. The objective was to review the CYP21A2 mutations' distribution among Brazilian regions.Two reviewers screened Brazilian papers up to February 2020 in five databases. The pair-wise comparison test and Holm method were used in the statistical analysis. Nine studies were selected, comprising 769 patients from all regions. Low proportion of males and salt-wasters was identified in the North and Northeast regions, although without significant difference. Large gene rearrangements also had a low frequency, except in the Center-West and South regions (p < 0.05). The most frequent mutations were p.I172N, IVS2-13A/C>G, p.V281L and p.Q318X, and significant differences in their distributions were found: p.V281L was more frequent in the Southeast and p.Q318X in the Center-West and Northeast regions (p < 0.05). Thirteen new mutations were identified in 3.8%-15.2% of alleles, being more prevalent in the North region, and six mutations presented a founder effect gene. Genotype-phenotype correlation varied from 75.9%-97.3% among regions. The low prevalence of the salt-wasting form, affected males and severe mutations in some regions indicated pitfalls in the clinical diagnosis. The good genotype-phenotype correlation confirms the usefulness of molecular diagnosis; however, the Brazilian population also presents significant prevalence of novel mutations, which should be considered for a molecular panel.
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ABSTRACT Primary adrenal insufficiency (PAI) is characterized by the inability of the adrenal cortex to produce sufficient amounts of glucocorticoids and/or mineralocorticoids. Addison's disease (AD) and congenital adrenal hyperplasia (CAH) are the most frequent disorders in adults and children, respectively. Despite the diagnostic advances and the availability of glucocorticoid and mineralocorticoid replacements, adrenal crisis (AC) is still a potentially lethal condition contributing to the increased mortality, not only during the first year of life, but also throughout life. Failure in increasing glucocorticoid doses during acute stress, when greater amounts of glucocorticoids are required, can lead to AC and an increase morbimortality rate of PAI. Considering a mortality rate of 0.5 per 100 patient years, up to 1,500 deaths from AC are expected in Brazil in the coming decade, which represents an alarming situation. The major clinical features are hypotension and volume depletion. Nonspecific symptoms such as fatigue, lack of energy, anorexia, nausea, vomiting, and abdominal pain are common. The main precipitating factors are gastrointestinal diseases, other infectious disease, stressful events (e.g., major pain, surgery, strenuous physical activity, heat, and pregnancy), and withdrawal of glucocorticoid therapy. Suspected AC requires immediate therapeutic action with intravenous (iv) hydrocortisone, fluid infusion, monitoring support, and antibiotics if necessary. AC is best prevented through patient education, precocious identification and by adjusting the glucocorticoid dosage in stressor situations. The emergency card, warning about acute glucocorticoid replacement, has high value in reducing the morbidity and mortality of AC.
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Humains , Enfant , Adulte , Maladie d'Addison , Insuffisance surrénale/étiologie , Hyperplasie congénitale des surrénales , Hydrocortisone , Glucocorticoïdes/usage thérapeutiqueRésumé
ABSTRACT Polycystic ovary syndrome (PCOS) is a common and complex endocrine disorder that affects 5-20% of reproductive age women. PCOS clinical symptoms include hirsutism, menstrual dysfunction, infertility, obesity and metabolic syndrome. There is a wide heterogeneity in clinical manifestations and metabolic complications. The pathogenesis of PCOS is not fully elucidated, but four aspects seem to contribute to the syndrome to different degrees: increased ovarian and/or adrenal androgen secretion, partial folliculogenesis arrest, insulin resistance and neuroendocrine axis dysfunction. A definitive etiology remains to be elucidated, but PCOS has a strong heritable component indicated by familial clustering and twin studies. Genome Wide Association Studies (GWAS) have identified several new risk loci and candidate genes for PCOS. Despite these findings, the association studies have explained less than 10% of heritability. Therefore, we could speculate that different phenotypes and subphenotypes are caused by rare private genetic variants. Modern genetic studies, such as whole exome and genome sequencing, will help to clarify the contribution of these rare genetic variants on different PCOS phenotypes. Arch Endocrinol Metab. 2018;62(3):352-61
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Humains , Femelle , Syndrome des ovaires polykystiques/génétique , PhénotypeRésumé
SUMMARY Isolated growth hormone deficiency (IGHD) is the most common pituitary hormone deficiency and, clinically, patients have delayed bone age. High sequence similarity between CYP21A2 gene and CYP21A1P pseudogene poses difficulties for exome sequencing interpretation. A 7.5 year-old boy born to second-degree cousins presented with severe short stature (height SDS −3.7) and bone age of 6 years. Clonidine and combined pituitary stimulation tests revealed GH deficiency. Pituitary MRI was normal. The patient was successfully treated with rGH. Surprisingly, at 10.8 years, his bone age had advanced to 13 years, but physical exam, LH and testosterone levels remained prepubertal. An ACTH stimulation test disclosed a non-classic congenital adrenal hyperplasia due to 21-hydroxylase deficiency explaining the bone age advancement and, therefore, treatment with cortisone acetate was added. The genetic diagnosis of a homozygous mutation in GHRHR (p.Leu144His), a homozygous CYP21A2 mutation (p.Val282Leu) and CYP21A1P pseudogene duplication was established by Sanger sequencing, MLPA and whole-exome sequencing. We report the unusual clinical presentation of a patient born to consanguineous parents with two recessive endocrine diseases: non-classic congenital adrenal hyperplasia modifying the classical GH deficiency phenotype. We used a method of paired read mapping aided by neighbouring mis-matches to overcome the challenges of exome-sequencing in the presence of a pseudogene.
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Humains , Mâle , Nourrisson , Enfant , Dysplasies osseuses/génétique , Steroid 21-hydroxylase/génétique , Récepteur aux neuropeptides/génétique , Hyperplasie congénitale des surrénales/génétique , Nanisme hypophysaire/génétique , Pedigree , Phénotype , Dysplasies osseuses/étiologie , Récepteur hormones hypothalamiques hypophysotropes régulatrices/génétique , Hyperplasie congénitale des surrénales/complications , Consanguinité , Nanisme hypophysaire/complications , MutationRésumé
SUMMARY P450 oxidoreductase deficiency (PORD) is a variant of congenital adrenal hyperplasia that is caused by POR gene mutations. The POR gene encodes a flavor protein that transfers electrons from nicotinamide adenine dinucleotide phosphate (NADPH) to all microsomal cytochrome P450 type II (including 21-hydroxylase, 17α-hydroxylase 17,20 lyase and aromatase), which is fundamental for their enzymatic activity. POR mutations cause variable impairments in steroidogenic enzyme activities that result in wide phenotypic variability ranging from 46,XX or 46,XY disorders of sexual differentiation, glucocorticoid deficiency, with or without skeletal malformations similar to Antley-Bixler syndrome to asymptomatic newborns diagnosed during neonatal screening test. Little is known about the PORD long-term evolution. We described a 46,XX patient with mild atypical genitalia associated with severe bone malformation, who was diagnosed after 13 years due to sexual infantilism. She developed large ovarian cysts and late onset adrenal insufficiency during follow-up, both of each regressed after hormone replacement therapies. We also described a late surgical approach for the correction of facial hypoplasia in a POR patient.
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OBJECTIVES: We aimed to investigate whether glucocorticoid receptor gene polymorphisms are associated with clinical and metabolic profiles in patients with polycystic ovary syndrome. Polycystic ovary syndrome is a complex endocrine disease that affects 5-8% of women and may be associated with metabolic syndrome, which is a risk factor for cardiovascular disease. Cortisol action and dysregulation account for metabolic syndrome development in the general population. As glucocorticoid receptor gene (NR3C1) polymorphisms regulate cortisol sensitivity, we hypothesized that variants of this gene may be involved in the adverse metabolic profiles of patients with polycystic ovary syndrome. METHOD: Clinical, metabolic and hormonal profiles were evaluated in 97 patients with polycystic ovary syndrome who were diagnosed according to the Rotterdam criteria. The alleles of the glucocorticoid gene were genotyped. Association analyses were performed using the appropriate statistical tests. RESULTS: Obesity and metabolic syndrome were observed in 42.3% and 26.8% of patients, respectively. Body mass index was positively correlated with blood pressure, triglyceride, LDL-c, total cholesterol, glucose and insulin levels as well as HOMA-IR values and inversely correlated with HDL-c and SHBG levels. The BclI and A3669G variants were found in 24.7% and 13.4% of alleles, respectively. BclI carriers presented a lower frequency of insulin resistance compared with wild-type subjects. CONCLUSION: The BclI variant is associated with a lower frequency of insulin resistance in women with polycystic ovary syndrome. Glucocorticoid gene polymorphism screening during treatment of the syndrome may be useful for identifying subgroups of at-risk patients who would benefit the most from personalized treatment. .
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Adulte , Femelle , Humains , Jeune adulte , Syndrome des ovaires polykystiques/génétique , Syndrome des ovaires polykystiques/métabolisme , Polymorphisme génétique/génétique , Récepteurs aux glucocorticoïdes/génétique , Allèles , Indice de masse corporelle , Cholestérol , Dosage fluoroimmunologique , Fréquence d'allèle , Gènes bcl-1/génétique , Hypertension artérielle/génétique , Hypertension artérielle/métabolisme , Insulinorésistance/génétique , Syndrome métabolique X/génétique , Syndrome métabolique X/métabolisme , Obésité/génétique , Obésité/métabolisme , Réaction de polymérisation en chaîne , Facteurs de risque , Statistique non paramétrique , Facteurs tempsRésumé
Environmental agencies have identified a growing number of environmental contaminants that have endocrine disrupting activity, and these can become a major public health problem. It is suggested that endocrine disruptors could account for the higher-than-expected increase in the prevalence of some non-communicable diseases, such as obesity, diabetes, thyroid diseases, and some cancers. Several endocrine Disrupting Chemicals (EDCs), such as pesticides, bisphenol A, phthalates, dioxins, and phytoestrogens, can interact with the female reproductive system and lead to endocrine disruption. Initially, it was assumed that EDCs exert their effects by binding to hormone receptors and transcription factors, but it is currently known that they may also alter the expression of enzymes involved in the synthesis or catabolism of steroids. Biomonitoring studies have identified these compounds in adults, children, pregnant women, and fetuses. Among the diseases of the female reproductive tract associated with EDCs exposure are the following: precocious puberty, polycystic ovary syndrome, and premature ovarian failure. The different populations of the world are exposed to a great number of chemicals through different routes of infection; despite the various available studies, there is still much doubt regarding the additive effect of a mixture of EDCs with similar mechanisms of action.
As diversas agências de controle ambiental têm identificado um crescente número de contaminantes ambientais que apresentam atividade de desregulador endócrino e estes poderão se tornar um dos maiores problemas de saúde pública. Sugere-se que os Desreguladores Endócrinos (EDCs) poderiam justificar o aumento na prevalência de algumas doenças não transmissíveis acima do esperado, como, por exemplo, obesidade, diabetes, doenças tireoidianas e alguns tipos de cânceres. Vários EDCs, como pesticidas, bisfenol A, ftalatos, dioxinas e fitoestrógenos, podem interagir com o sistema reprodutivo feminino e levar à desregulação endócrina. Inicialmente, supunha-se que os EDCs exercessem seus efeitos através da ligação com receptores hormonais e fatores de transcrição, mas, atualmente, sabe-se que também podem alterar a expressão de enzimas envolvidas na síntese ou no catabolismo dos esteroides. Estudos de biomonitoramento têm identificado esses compostos em adultos, crianças, gestantes e em fetos. Entre as patologias do trato reprodutor feminino associadas à exposição aos EDCs, destacam-se: puberdade precoce, síndrome dos ovários policísticos e falência ovariana prematura. As diversas populações estão expostas a um grande número de substâncias químicas, através de diferentes vias de contaminação. Apesar dos diferentes estudos disponíveis, ainda permanece uma grande dúvida sobre o efeito aditivo de uma mistura de EDCs com similar mecanismo de ação.
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Animaux , Femelle , Humains , Souris , Grossesse , Troubles du développement sexuel/induit chimiquement , Perturbateurs endocriniens/toxicité , Exposition environnementale/effets indésirables , Maladies ovariennes/induit chimiquement , Dioxines/toxicité , Pesticides/toxicité , Puberté précoce/induit chimiquementRésumé
OBJECTIVES: Patients with Cushing's disease exhibit wide phenotypic variability in the severity of obesity, diabetes and hypertension. In the general population, several glucocorticoid receptor genes (NR3C1) and HSD11B1 polymorphisms are associated with altered glucocorticoid sensitivity and/or metabolism, resulting in an increased or reduced risk of an adverse metabolic profile. Our aim was to analyze the association of NR3C1 and HSD11B1 gene variants with the severity of some clinical and hormonal features of Cushing's disease. METHODS: Sixty-four patients presenting with Cushing's disease were diagnosed based on adrenocorticotrophic hormone levels, high-dose dexamethasone suppression tests and/or inferior petrosal sinus sampling and magnetic resonance imaging. The A3669G, ER22/23EK, N363S BclI-NR3C1 and HSD11B1-rs12086634 variants were screened. RESULTS: The BclI, HSD11B1-rs12086634 and A3669G variants were found in 36%, 19.5% and 14% of alleles, respectively. The N363S and ER22/23EK polymorphisms were identified in heterozygosis once in only two patients (1.5% of alleles). There were no differences in the weight gain or prevalence of diabetes and hypertension in the patients carrying the abovementioned alleles compared to the wild-type carriers. Interestingly, the mean body mass index (BMI) of the BclI carriers was significantly higher than the non-carriers (34.4±7 kg/m2 vs. 29.6±4.7 kg/m2, respectively). None of the polymorphisms were associated with the basal adrenocorticotrophic hormone, FU levels or F level after dexamethasone suppression testing. CONCLUSION: Although Cushing's disease results from increased glucocorticoid secretion, we observed that interindividual variability in the peripheral glucocorticoid sensitivity, mediated by the glucocorticoid receptor, could modulate the obesity phenotype. .
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Femelle , Humains , Mâle , Adulte d'âge moyen , Allèles , /génétique , Prédisposition génétique à une maladie , Hypersécrétion hypophysaire d'ACTH/génétique , Polymorphisme génétique/génétique , Récepteurs aux glucocorticoïdes/génétique , Indice de masse corporelle , Génotype , Phénotype , Hypersécrétion hypophysaire d'ACTH/sangRésumé
OBJECTIVE: The protocols for glucocorticoid replacement in children with salt wasting 21-hydroxylase deficiency are well established; however, the current recommendation for mineralocorticoid replacement is general and suggests individualized dose adjustments. This study aims to retrospectively review the 9-∝-fludrocortisone dose regimen in salt wasting 21-hydroxylase deficient children who have been adequately treated during infancy. METHODS: Twenty-three salt wasting 21-hydroxylase deficient patients with good anthropometric and hormonal control were followed in our center since diagnosis. The assessments of cortisone acetate and 9-∝-fludrocortisone doses, anthropometric parameters, and biochemical and hormonal levels were rigorously evaluated in pre-determined intervals from diagnosis to two years of age. RESULTS: The 9-∝-fludrocortisone doses decreased over time during the first and second years of life; the median fludrocortisone doses were 200 µg at 0-6 months, 150 µg at 7-18 months and 125 µg at 19-24 months. The cortisone acetate dose per square meter was stable during follow-up (median = 16.8 mg/m²/day). The serum sodium, potassium and plasma rennin activity levels during treatment were normal, except in the first month of life, when periodic 9-∝-fludrocortisone dose adjustments were made. CONCLUSIONS: The mineralocorticoid needs of salt wasting 21-hydroxylase deficient patients are greater during early infancy and progressively decrease during the first two years of life, which confirms that a partial aldosterone resistance exists during this time. Our study proposes a safety regiment for mineralocorticoid replacement during this critical developmental period.
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Femelle , Humains , Nourrisson , Nouveau-né , Mâle , Hyperplasie congénitale des surrénales/traitement médicamenteux , Anti-inflammatoires/administration et posologie , Fludrocortisone/administration et posologie , Facteurs âges , Anthropométrie , Hyperplasie congénitale des surrénales/génétique , Cortisone/administration et posologie , Cortisone/analogues et dérivés , Études rétrospectives , Statistique non paramétrique , Facteurs temps , Résultat thérapeutiqueRésumé
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 percent of newborns presented false-positive results using the cutoff level > 20 ng/mL for all groups. Neonates of low birthweight made up 69 percent 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 percent), 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.
OBJETIVO: Avaliamos retrospectivamente os valores da 17OHP ajustados para o peso ao nascimento para melhorar a eficiência da triagem neonatal. SUJEITOS E MÉTODOS: 67.640 recém-nascidos com amostras coletadas entre 2-7 dias de vida. Uma segunda amostra foi solicitada na presença de testes com valores da 17OHP > 20 ng/mL. 17OHP dosada pelo método DELFIA- B024-112 e correlacionada com o peso ao nascimento: G1 < 1.500 g, G2 1.501-2.000 g, G3 2.000-2.500 g e G4 > 2.500 g. Pontos de corte da 17OHP foram determinados para cada grupo usando os percentis 97,5th, 99th, 99,5th e 99,8th. RESULTADOS: Falso-positivos ocorreram em 5 por cento dos resultados com o ponto de corte > 20 ng/mL, dos quais 69 por cento eram prematuros. Sete recém-nascidos apresentaram deficiência da 21-hidroxilase e, exceto em um, os valores da 17OHP foram > 120 ng/mL. Somente o valor da 17OHP do 99,8th apresentou maior valor preditivo positivo (2 por cento) e menor índice de falso-positivos. CONCLUSÕES: Sugerimos o valor da 17OHP do 99,8th ajustado para o peso ao nascimento para se reduzir a taxa de resultados falso-positivos da triagem neonatal.
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Femelle , Humains , Nouveau-né , Mâle , /sang , Hyperplasie congénitale des surrénales/diagnostic , Poids de naissance , Dépistage néonatal/méthodes , Brésil/épidémiologie , Faux positifs , Dosage fluoroimmunologique/méthodes , Valeur prédictive des tests , Valeurs de référence , Études rétrospectives , Statistique non paramétriqueRésumé
INTRODUCTION: PXR polymorphisms have been implicated in modulating CYP3A4 and PXR expression, potentially accounting for interindividual differences in drug metabolism. The prevalence of PXR polymorphisms varies among ethnic groups and data on the allelic distribution in the highly mixed Brazilian population is lacking. The aim of this study was to analyze genetic variations in the PXR gene in Brazilians and to compare the results to other ethnic groups. METHODS: DNA samples from 117 healthy Brazilians underwent PCR amplification and sequencing. RESULTS: Eleven polymorphisms were identified, 3 of which are highly associated with differences in CYP3A4 expression. We also identified 1 new synonymous variant in 1.3 percent of the alleles. Among the functional polymorphisms, -25913 C>T and -6994T>C occurred at a higher frequency comparedtothe Africanalleles (p < 0.05) but at a lower frequency compared to Caucasian alleles. The 8055 C>T allele was found at a similar frequency to those described in Caucasians and Africans (p > 0.05). CONCLUSION: We observed that functional variants of the PXR were frequent in our sample of the Brazilian population. Our results suggest that PXR gene variants may be of interest in pharmacogenetic studies involving Brazilians.
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Adolescent , Adulte , Femelle , Humains , Mâle , Jeune adulte , Polymorphisme génétique/génétique , Récepteurs aux stéroïdes/génétique , Allèles , Brésil/ethnologie , /métabolisme , Exons , Ethnies/génétique , Fréquence d'allèle , Réaction de polymérisation en chaîneRésumé
INTRODUCTION: 21-hydroxylase deficiency is an autosomal recessive disorder that causes glucocorticoid deficiency and increased androgen production. Treatment is based on glucocorticoid replacement; however, interindividual variability in the glucocorticoid dose required to achieve adequate hormonal control has been observed. OBJECTIVE: The present study aimed to evaluate the association between polymorphic variants involved inglucocorticoid action and/or metabolism and the mean daily glucocorticoid dose in 21-hydroxylase deficiency patients. METHODS: We evaluated 53 patients with classical forms of 21-hydroxylase deficiency who were receiving cortisone acetate. All patients were between four and six years of age and had normal androgen levels. RESULTS: The P450 oxidoreductase A503V, HSD11B1 rs12086634, and CYP3A7*1C variants were found in 19 percent, 11.3 percent and 3.8 percent of the patients, respectively. The mean ± SD glucocorticoid dose in patients with the CYP3A7*1C and wild-type alleles was 13.9 ± 0.8 and 19.5 ± 3.2 mg/m²/d, respectively. We did not identify an association between the P450 oxidoreductase or HSD11B1 allelic variants and the mean glucocorticoid dose. CONCLUSION: Patients carrying the CYP3A7*1C variant required a significantly lower mean glucocorticoid dose. Indeed, the CYP3A7*1C allele accounted for 20 percent of the variability in the cortisone acetate dose. The analysis of genes involved in glucocorticoid metabolism may be useful in the optimization of treatment of 21-hydroxylase deficiency.
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Enfant , Enfant d'âge préscolaire , Femelle , Humains , Nourrisson , Mâle , Hyperplasie congénitale des surrénales/traitement médicamenteux , Hyperplasie congénitale des surrénales/génétique , Cortisone/analogues et dérivés , Glucocorticoïdes/administration et posologie , Oxidoreductases/génétique , Polymorphisme génétique , Hyperplasie congénitale des surrénales/enzymologie , Cortisone/administration et posologie , Hormonothérapie substitutiveRésumé
Analisamos as características clínicas e moleculares de 205 pacientes portadores das diferentes formas clínicas da deficiência da 21-hidroxilase, com diagnóstico hormonal e molecular definidos. As mutações mais freqüentes foram a I2 splice na forma perdedora de sal, a I172N na forma virilizante simples e a V281L na forma não clássica, com freqüências semelhantes às de outros estudos. Obtivemos baixa freqüência de deleção do gene da 21-hidroxilase, de forma semelhante ao identificado nas populações argentina e mexicana. Cinco mutações novas foram descritas em nossa população: G424S, H28+C, Ins 1003 1004 A, R408C e IVS2-2A>G. A severidade do genótipo também se correlacionou diretamente com níveis mais elevados de 17OH-progesterona e de testosterona. As mutações foram classificadas em três grupos, de acordo com o comprometimento da atividade enzimática observado in vitro: Grupo A: atividade de 0-2 por cento; Grupo B: atividade de 3-7 por cento e Grupo C: atividade >20 por cento. Houve forte correlação do grupo A com a forma perdedora de sal, do grupo B com a forma virilizante simples e do grupo C com a forma não clássica. A mutação I2 splice (Grupo A) em homo ou hemizigose conferiu o fenótipo de forma clássica, embora tanto a forma perdedora de sal quanto a forma virilizante simples tenham sido identificadas. A boa correlação do genótipo com o fenótipo na HAC-21OH permite sua aplicação na prática clínica, para o aconselhamento genético, diagnóstico e tratamento pré-natal das gestações de risco para a forma clássica da HAC-21OH e para confirmação diagnóstica após screening neonatal da HAC-21OH, exceto na presença da mutação I2splice.
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Enfant , Femelle , Humains , Mâle , Hyperplasie congénitale des surrénales/génétique , Génotype , Mutation , PhénotypeRésumé
OBJETIVO: Padronizar a técnica de Southern blotting usando hibridização com material não radioativo para detectar grandes rearranjos no gene CYP21A2 em uma amostra da população brasileira com hiperplasia adrenal congênita. MÉTODO: Foram estudados 42 pacientes, 2 dos quais aparentados, totalizando 80 alelos não relacionados. As amostras de DNA foram obtidas de sangue periférico, digeridas com enzima de restrição Taq I, realizado Southern blotting e hibridizadas com sonda marcada com biotina. RESULTADOS: O método se mostrou eficaz, com resultados similares aos encontrados ao utilizar a metodologia com material radioativo. Foram encontradas 2,5% de deleção do CYP21A2, 8,8% de grandes conversões, 3,8% de deleção do CYP21A1P e 6,3% de duplicação do CYP21A1P. Estas freqüências foram similares às encontradas em nosso estudo prévio, onde um número significante de casos foi estudado. Um bom padrão de hibridização foi alcançado utilizando menor quantidade de DNA (5mg) e a emissão de sinais foi observada entre 5 minutos e 1 hora de exposição. CONCLUSÕES: Padronizamos uma técnica de Southern blotting/ hibridização com material não radioativo (biotina) para a pesquisa de grandes rearranjos no gene CYP21A2 com bons resultados. Apesar de ser mais trabalhoso, este método é mais rápido, utiliza menores quantidades de DNA e, principalmente, evita problemas com o uso de radioatividade.
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Femelle , Humains , Mâle , Hyperplasie congénitale des surrénales/génétique , Biotine/analogues et dérivés , Technique de Southern/méthodes , ADN , Nucléotides désoxycytidyliques , Réarrangement des gènes/génétique , Allèles , Biotine , Délétion de gène , Duplication de gène , Hybridation d'acides nucléiquesRésumé
O diagnóstico da forma näo clássica da deficiência da 21-hidroxilase (NC-21OH) é realizado na presença de manifestações hiperandrogênicas e valores da 17-hidroxiprogesterona (17OHP) basais >5ng/mL ou pós-ACTH >10ng/mL. Apresentamos os casos de duas crianças com pubarca precoce e com diagnóstico hormonal de forma NC-21OH, cujo estudo molecular do gene CYP21A2 confirmou o diagnóstico em apenas um caso. Isto nos levou a reavaliar o diagnóstico hormonal da forma NC-21OH através do estudo molecular em 58 pacientes com 17OHP pós-ACTH >10ng/mL. Apenas 37 (67 por cento) pacientes tiveram mutações identificadas em ambos os alelos. Nestes, os valores basais da 17OHP foram francamente elevados (>5ng/mL) em 70 por cento, normais em 11 por cento e, nos demais, entre 2 e 5ng/mL. O menor valor da 17OHP pós-ACTH neste grupo foi de 17ng/mL. Ao analisarmos 59 indivíduos heterozigotos obrigatórios para a deficiência da 21-hidroxilase, observamos dois casos com valores da 17OHP pós-ACTH de 11 e 15ng/mL, respectivamente. Estes dados sugerem que o atual critério diagnóstico hormonal da forma NC-21OH possa estar superestimando seu diagnóstico
Sujets)
Humains , Femelle , Enfant , Hyperplasie congénitale des surrénales , Puberté précoce , Hyperplasie congénitale des surrénales , Cortisone , Mutation/génétique , Puberté précoceRésumé
Hiperplasia adrenal congênita (HAC) é uma doença autossômica recessiva decorrente da alteraçäo de enzimas que participam da síntese do cortisol. As manifestações podem ser causadas pela deficiência do cortisol e, em alguns casos, aldosterona e pelo acúmulo de precursores. O objetivo desta revisäo é apresentar os mecanismos moleculares dos principais defeitos enzimáticos envolvidos na etiopatogênese da HAC. A deficiência da 21-hidroxilase (210H) ocorre em 95 por cento dos casos de HAC. Existem dois genes que codificam o P450c21: um ativo, CYP21, e um pseudogene CYP27P. Ambos säo altamente homólogos (98 por cento), o que favorece o emparelhamento desigual dos cromossomos homólogos durante a meiose, levando a duplicações e/ou deleções ou conversões desses genes. Adicionalmente, foram também descritas mutações de ponto, muitas delas presentes no pseudogene sugerindo microconversões. Mutações no gene CYP 1181 causam HAC por deficiência da 11 Rhidroxilase, forma esta que corresponde a 5 por cento dos casos. Algumas mutações säo recorrentes, situando-se principalmente entre os exons 6-8 que representaria uma área hot-spot no gene CYP 1781. A deficiência de 17-hidroxilase é causada por mutações no gene CYP77, que codificam uma proteína alterada, levando a deficiência total ou parcial de 17hidroxilaçäo e 17,20-liase ou deficiência isolada de 17,20-Base. Finalmente, deficiência de 3B-HSD é causada por mutações no gene HSD3B2, que codifica a enzima 3B-HSD tipo II e estas mutações têm sido associadas tanto com a forma clássica como com a forma näo clássica da deficiência da 3B-HSD.