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CONTEXT: The pituitary gland is key for childhood growth, puberty, and metabolism. Pituitary dysfunction is associated with a spectrum of phenotypes, from mild to severe. Congenital Hypopituitarism (CH) is the most commonly reported pediatric endocrine dysfunction with an incidence of 1:4000, yet low rates of genetic diagnosis have been reported. OBJECTIVE: We aimed to unveil the genetic etiology of CH in a large cohort of patients from Argentina. METHODS: We performed whole exome sequencing of 137 unrelated cases of CH, the largest cohort examined with this method to date. RESULTS: Of the 137 cases, 19.1% and 16% carried pathogenic or likely pathogenic variants in known and new genes, respectively, while 28.2% carried variants of uncertain significance. This high yield was achieved through the integration of broad gene panels (genes described in animal models and/or other disorders), an unbiased candidate gene screen with a new bioinformatics pipeline (including genes high loss of function intolerance), and analysis of copy number variants. Three novel findings emerged. First, the most prevalent affected gene encodes the cell adhesion factor ROBO1. Affected children had a spectrum of phenotypes, consistent with a role beyond pituitary stalk interruption syndrome. Second, we found that CHD7 mutations also produce a phenotypic spectrum, not always associated with full CHARGE syndrome. Third, we add new evidence of pathogenicity in the genes PIBF1 and TBC1D32, and report 13 novel candidate genes associated with CH (e.g. PTPN6, ARID5B). CONCLUSION: Overall, these results provide an unprecedented insight into the diverse genetic etiology of hypopituitarism.
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Hypopituitarism, or the failure to secrete hormones produced by the anterior pituitary (adenohypophysis) and/or to release hormones from the posterior pituitary (neurohypophysis), can be congenital or acquired. When more than one pituitary hormone axis is impaired, the condition is known as combined pituitary hormone deficiency (CPHD). The deficiency may be primarily due to a hypothalamic or to a pituitary disorder, or concomitantly both, and has a negative impact on target organ function. This review focuses on the pathophysiology, diagnosis and management of anterior pituitary hormone deficiency in the pediatric age. Congenital hypopituitarism is generally due to genetic disorders and requires early medical attention. Exposure to toxicants or intrauterine infections should also be considered as potential etiologies. The molecular mechanisms underlying the fetal development of the hypothalamus and the pituitary are well characterized, and variants in the genes involved therein may explain the pathophysiology of congenital hypopituitarism: mutations in the genes expressed in the earliest stages are usually associated with syndromic forms whereas variants in genes involved in later stages of pituitary development result in non-syndromic forms with more specific hormone deficiencies. Tumors or lesions of the (peri)sellar region, cranial radiation therapy, traumatic brain injury and, more rarely, other inflammatory or infectious lesions represent the etiologies of acquired hypopituitarism. Hormone replacement is the general strategy, with critical periods of postnatal life requiring specific attention.
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Hipopituitarismo , Humanos , Hipopituitarismo/diagnóstico , Hipopituitarismo/terapia , Criança , Hormônios Adeno-Hipofisários/deficiência , Hormônios Adeno-Hipofisários/metabolismoRESUMO
Growth hormone (GH) binding to GH receptor activates janus kinase 2 (JAK2)-signal transducer and activator of transcription 5b (STAT5b) pathway, which stimulates transcription of insulin-like growth factor-1 (IGF1), insulin-like growth factor binding protein 3 (IGFBP3) and insulin-like growth factor acid-labile subunit (IGFALS). Although STAT5B deficiency was established as an autosomal recessive disorder, heterozygous dominant-negative STAT5B variants have been reported in patients with less severe growth deficit and milder immune dysfunction. We developed an in vivo functional assay in zebrafish to characterize the pathogenicity of three human STAT5B variants (p.Ala630Pro, p.Gln474Arg and p.Lys632Asn). Overexpression of human wild-type (WT) STAT5B mRNA and its variants led to a significant reduction of body length together with developmental malformations in zebrafish embryos. Overexpression of p.Ala630Pro, p.Gln474Arg or p.Lys632Asn led to an increased number of embryos with pericardial edema, cyclopia and bent spine compared with WT STAT5B. Although co-injection of WT and p.Gln474Arg and WT and p.Lys632Asn STAT5B mRNA in zebrafish embryos partially or fully rescues the length and the developmental malformations in zebrafish embryos, co-injection of WT and p.Ala630Pro STAT5B mRNA leads to a greater number of embryos with developmental malformations and a reduction in body length of these embryos. These results suggest that these variants could interfere with endogenous stat5.1 signaling through different mechanisms. In situ hybridization of zebrafish embryos overexpressing p.Gln474Arg and p.Lys632Asn STAT5B mRNA shows a reduction in igf1 expression. In conclusion, our study reveals the pathogenicity of the STAT5B variants studied.
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Fator de Transcrição STAT5 , Peixe-Zebra , Animais , Humanos , Peixe-Zebra/genética , Peixe-Zebra/metabolismo , Fator de Transcrição STAT5/genética , Fator de Transcrição STAT5/metabolismo , Hormônio do Crescimento , Transdução de Sinais/genética , RNA Mensageiro , Fator de Crescimento Insulin-Like I/genéticaRESUMO
PURPOSE: Congenital hypopituitarism (CH) can present in isolation or with other birth defects. Mutations in multiple genes can cause CH, and the use of a genetic screening panel could establish the prevalence of mutations in known and candidate genes for this disorder. It could also increase the proportion of patients that receive a genetic diagnosis. METHODS: We conducted target panel genetic screening using single-molecule molecular inversion probes sequencing to assess the frequency of mutations in known hypopituitarism genes and new candidates in Argentina. We captured genomic deoxyribonucleic acid from 170 pediatric patients with CH, either alone or with other abnormalities. We performed promoter activation assays to test the functional effects of patient variants in LHX3 and LHX4. RESULTS: We found variants classified as pathogenic, likely pathogenic, or with uncertain significance in 15.3% of cases. These variants were identified in known CH causative genes (LHX3, LHX4, GLI2, OTX2, HESX1), in less frequently reported genes (FOXA2, BMP4, FGFR1, PROKR2, PNPLA6) and in new candidate genes (BMP2, HMGA2, HNF1A, NKX2-1). CONCLUSION: In this work, we report the prevalence of mutations in known CH genes in Argentina and provide evidence for new candidate genes. We show that CH is a genetically heterogeneous disease with high phenotypic variation and incomplete penetrance, and our results support the need for further gene discovery for CH. Identifying population-specific pathogenic variants will improve the capacity of genetic data to predict eventual clinical outcomes.
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Doenças do Sistema Endócrino/genética , Testes Genéticos/estatística & dados numéricos , Hipopituitarismo/genética , Mutação/genética , Adolescente , Adulto , Argentina , Criança , Pré-Escolar , Feminino , Heterogeneidade Genética , Humanos , Lactente , Proteínas com Homeodomínio LIM/genética , Masculino , Fenótipo , Polimorfismo de Nucleotídeo Único , Fatores de Transcrição/genética , Adulto JovemRESUMO
La osteoporosis es un trastorno para tener en cuenta en niños con patologías crónicas graves o con algunas enfermedades genéticas que predisponen al incremento de la fragilidad ósea. La osteoporosis primaria es una entidad con etiologías emergentes y puede ocurrir en forma sindrómica. La asociación con pliegues retinianos congénitos debe orientar al diagnóstico de osteoporosis-pseudoglioma (OMIM 259770), síndrome poco frecuente (prevalencia de 1/2000000), que se origina por la pérdida de función de la proteína LRP5 (low-density lipoprotein receptor-related protein 5) y compromete la vía de señalización de Wnt/ß-catenina. Se presenta el caso de un niño con pliegues retinianos congénitos, ceguera progresiva y múltiples fracturas cuyo estudio clínico, bioquímico y genético confirmó el diagnóstico de osteoporosis primaria debido a una nueva variante inactivante en el gen LRP5 en homocigosis
Osteoporosis should be considered in children with severe chronic diseases or in association with some genetic diseases that bear an increased risk of bone fragility. Primary osteoporosis is an entity in which emerging aetiologies are being recognized. Its association with congenital retinal folds should guide the diagnosis to the Osteoporosis-Pseudoglioma syndrome (OMIM 259770), a rare disease (prevalence of 1/2000000), caused by the loss of function of the protein LRP5 (low-density lipoprotein receptor-related protein 5) resulting in the alteration of the Wnt/ß-catenin signalling pathway. We report the case of a child with congenital retinal folds, progressive loss of vision and multiple fractures whose clinical, biochemical and genetic studies confirmed the diagnosis of primary osteoporosis due to a novel homozygous inactivating variant in LRP5
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Humanos , Masculino , Criança , Osteoporose/diagnóstico , Osteoporose/terapia , Cegueira , Fraturas MúltiplasRESUMO
Osteoporosis should be considered in children with severe chronic diseases or in association with some genetic diseases that bear an increased risk of bone fragility. Primary osteoporosis is an entity in which emerging aetiologies are being recognized. Its association with congenital retinal folds should guide the diagnosis to the Osteoporosis-Pseudoglioma syndrome (OMIM 259770), a rare disease (prevalence of 1/2 000 000), caused by the loss of function of the protein LRP5 (low-density lipoprotein receptor-related protein 5) resulting in the alteration of the Wnt/ß-catenin signalling pathway. We report the case of a child with congenital retinal folds, progressive loss of vision and multiple fractures whose clinical, biochemical and genetic studies confirmed the diagnosis of primary osteoporosis due to a novel homozygous inactivating variant in LRP5.
La osteoporosis es un trastorno para tener en cuenta en niños con patologías crónicas graves o con algunas enfermedades genéticas que predisponen al incremento de la fragilidad ósea. La osteoporosis primaria es una entidad con etiologías emergentes y puede ocurrir en forma sindrómica. La asociación con pliegues retinianos congénitos debe orientar al diagnóstico de osteoporosis-pseudoglioma (OMIM 259770), síndrome poco frecuente (prevalencia de 1/2 000 000), que se origina por la pérdida de función de la proteína LRP5 (low-density lipoprotein receptor-related protein 5) y compromete la vía de señalización de Wnt/ß-catenina. Se presenta el caso de un niño con pliegues retinianos congénitos, ceguera progresiva y múltiples fracturas cuyo estudio clínico, bioquímico y genético confirmó el diagnóstico de osteoporosis primaria debido a una nueva variante inactivante en el gen LRP5 en homocigosis.
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Osteogênese Imperfeita/diagnóstico , Criança , Marcadores Genéticos , Testes Genéticos , Homozigoto , Humanos , Proteína-5 Relacionada a Receptor de Lipoproteína de Baixa Densidade/genética , Masculino , Mutação , Osteogênese Imperfeita/genéticaRESUMO
OBJECTIVE: to describe the marked variability in clinical and biochemical patterns that are associated with a p.R209H GH1 missense variant in a large Argentinean pedigree, which makes the diagnosis of GHD elusive. DESIGN: We describe a non-consanguineous pedigree composed by several individuals with short stature, including 2 pediatric patients with typical diagnosis of isolated growth hormone deficiency (IGHD) and 4 other siblings with severe short stature, low serum IGF-1 and IGFBP-3, but normal stimulated GH levels, suggesting growth hormone insensitivity (GHI) in the latter group. RESULTS: Patients with classical IGHD phenotype carried a heterozygous variant in GH1: c.626G>A (p.R209H). Data from the extended pedigree suggested GH1 as the initial candidate gene, which showed the same pathogenic heterozygous GH1 variant in the four siblings with short stature and a biochemical pattern of GHI. CONCLUSIONS: We suggest considering GH1 sequencing in children with short stature associated to low IGF-1 and IGFBP-3 serum levels, even in the context of normal response to growth hormone provocative testing (GHPT).
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Estatura , Nanismo Hipofisário/genética , Hormônio do Crescimento Humano/genética , Mutação de Sentido Incorreto , Adolescente , Adulto , Argentina , Criança , Pré-Escolar , Técnicas de Diagnóstico Endócrino , Nanismo Hipofisário/metabolismo , Nanismo Hipofisário/fisiopatologia , Feminino , Transtornos do Crescimento/genética , Transtornos do Crescimento/metabolismo , Transtornos do Crescimento/fisiopatologia , Heterozigoto , Homozigoto , Hormônio do Crescimento Humano/metabolismo , Humanos , Proteína 3 de Ligação a Fator de Crescimento Semelhante à Insulina/metabolismo , Fator de Crescimento Insulin-Like I/metabolismo , Masculino , Pessoa de Meia-Idade , Linhagem , Adulto JovemRESUMO
Introduction: Practice guidelines cannot recommend establishing a diagnosis of growth hormone deficiency (GHD) without performing growth hormone stimulation tests (GHST) in children with risk factors, due to the lack of sufficient evidence. Objective: Our goal was to generate an evidence-based prediction rule to diagnose GHD in children with growth failure and clinically identifiable risk factors. Methods: We studied a cohort of children with growth failure to build the prediction model, and a second, independent cohort to validate the prediction rule. To this end, we assessed the existence of: pituitary dysgenesis, midline abnormalities, (supra)sellar tumor/surgery, CNS infection, traumatic brain injury, cranial radiotherapy, chemotherapy, genetic GHD, pituitary hormone deficiencies, and neonatal hypoglycemia, cholestasis, or hypogenitalism. Selection of variables for model building was performed using artificial intelligence protocols. Specificity of the prediction rule was the main outcome measure in the validation set. Results: In the first cohort (n=770), the resulting prediction rule stated that a patient would have GHD if (s)he had: pituitary dysgenesis, or two or more anterior pituitary deficiencies, or one anterior pituitary deficiency plus: neonatal hypoglycemia or hypogenitalism, or diabetes insipidus, or midline abnormalities, or (supra)sellar tumor/surgery, or cranial radiotherapy ≥18 Gy. In the validation cohort (n=161), the specificity of the prediction rule was 99.2% (95% CI: 95.6-100%). Conclusions: This clinical rule predicts the existence of GHD with high specificity in children with growth disorders and clinically identifiable risk factors, thus providing compelling evidence to recommend that GHD can be safely diagnosed without recurring to GHST in neonates and children with growth failure and specific comorbidities.
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Algoritmos , Estatura/fisiologia , Hormônio do Crescimento Humano/deficiência , Aprendizado de Máquina/normas , Encéfalo/diagnóstico por imagem , Encéfalo/metabolismo , Criança , Pré-Escolar , Estudos de Coortes , Nanismo Hipofisário/sangue , Nanismo Hipofisário/diagnóstico por imagem , Feminino , Humanos , Masculino , Guias de Prática Clínica como Assunto/normas , Valor Preditivo dos Testes , Reprodutibilidade dos Testes , Fatores de RiscoRESUMO
BACKGROUND: IGF1 is a key factor in fetal and postnatal growth. To date, only three homozygous IGF1 gene defects leading to complete or partial loss of IGF1 activity have been reported in three short patients born small for gestational age. We describe the fourth patient with severe short stature presenting a novel homozygous IGF1 gene mutation. RESULTS: We report a boy born from consanguineous parents at 40 weeks of gestational age with intrauterine growth restriction and severe postnatal growth failure. Physical examination revealed proportionate short stature, microcephaly, facial dysmorphism, bilateral sensorineural deafness and mild global developmental delay. Basal growth hormone (GH) fluctuated from 0.2 to 29 ng/mL, while IGF1 levels ranged from -1.15 to 2.95 SDS. IGFBP3 was normal-high. SNP array delimited chromosomal regions of homozygosity, including 12q23.2 where IGF1 is located. IGF1 screening by HRM revealed a homozygous missense variant NM_000618.4(IGF1):c.322T>C, p.(Tyr108His). The change of the highly conserved Tyr60 in the mature IGF1 peptide was consistently predicted as pathogenic by multiple bioinformatic tools. Tyr60 has been described to be critical for IGF1 interaction with type 1 IGF receptor (IGF1R). In vitro, HEK293T cells showed a marked reduction of IGF1R phosphorylation after stimulation with serum from the patient as compared to sera from age-matched controls. Mutant IGF1 was also less efficient in inducing cell growth. CONCLUSION: The present report broadens the spectrum of clinical and biochemical presentation of homozygous IGF1 defects and underscores the variability these patients may present depending on the IGF/IGF1R pathway activity.
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Transtornos do Crescimento/genética , Perda Auditiva Neurossensorial/genética , Fator de Crescimento Insulin-Like I/deficiência , Mutação de Sentido Incorreto/genética , Anormalidades Múltiplas/genética , Proliferação de Células , Biologia Computacional , Simulação por Computador , Retardo do Crescimento Fetal/genética , Células HEK293 , Homozigoto , Humanos , Lactente , Fator de Crescimento Insulin-Like I/genética , Masculino , Linhagem , Polimorfismo de Nucleotídeo Único/genética , Receptor IGF Tipo 1 , Receptores de Somatomedina/genética , Tirosina/genéticaRESUMO
La insuficiencia hipofisaria congénita es un trastorno originado en la alteración de la ontogenia de la glándula hipofisaria que determina la disminución o falta de trofinas hipofisarias: adrenocorticotropina, tirotropina, hormona de crecimiento, prolactina, gonadotrofinas y/u hormona antidiurética. Es una patología compleja e infrecuente que, debido a su signo sintomatología inespecífica, suele ser difícil de reconocer a edades tempranas, derivando en aumento de la morbilidad y eventualmente de la mortalidad. Durante el periodo neonatal, es característica la ictericia colestática asociada a hipoglucemias recurrentes. Puede formar parte de un cuadro sindrómico, siendo el más frecuente la displasia septoóptica, que asocia defectos de línea media y alteraciones oculares. La mayoría presenta anomalías anatómicas de la región selar y supraselar evidenciables en la Resonancia Magnética. El diagnóstico bioquímico tiene especificaciones particulares para la evaluación de cada trofina hipofisaria y de acuerdo a la edad del paciente. El tratamiento consiste en la terapia de reemplazo hormonal observándose buena respuesta en la mayoría de los pacientes. La detección precoz de los niños con insuficiencia hipofisaria permite la activación rápida y efectiva de una estrategia diagnóstica con la toma de muestras bioquímicas apropiadas, la consulta temprana al endocrinólogo infantil y la instauración del tratamiento específico
Congenital pituitary hormone deficiency is a disorder originated in pituitary gland ontogeny generating decrease or lack of pituitary hormones: adrenocorticotropin, thyrotropin, growth hormone, prolactin, gonadotropins and/or antidiuretic hormone. It is a complex and infrequent disease usually difficult to recognize at an early age due to its non-specific symptomatology, resulting in increased morbidity and eventual mortality. During the neonatal period, cholestatic jaundice associated with recurrent hypoglycaemia is frequent. Pituitary hormone deficiency can be part of a syndrome; the most frequent is septo-optic dysplasia, associating midline defects and ocular disorders. Most have anatomical anomalies of the sellar and suprasellar region seen in magnetic resonance imaging. Biochemical diagnosis has particular specifications for the evaluation of each pituitary hormone and varies according to patient´s age. The treatment consists in hormone replacement therapy and generally with good results. The early detection of children with pituitary hormone deficiency allows the rapid and effective activation of a diagnostic strategy, facilitates the appropriate biochemical samples, the early contact with the pediatric endocrinologist and the establishment of specific treatment