Caracterización clínica de pacientes chilenos con displasia fibrosa/síndrome de McCune-Albright / Clinical features of Chilean patients with Fibrous Dysplasia/McCune-Albright Syndrome

BACKGROUND: Fibrous Dysplasia/McCune-Albright Syndrome (FD/MAS) is characterized by a spectrum of manifestations that may include fibrous dysplasia of bone and multiple endocrinopathies. AIM: To describe the clinical spectrum, the study and follow-up of patients with FD/MAS cared at our institution. MATERIAL AND METHODS: Review of medical records of 12 pediatric and adult patients (11 women) who met the clinical and genetic diagnostic criteria for FD/ MAS. RESULTS: The patients' mean age at diagnosis was 4.9 ± 5.5 years. The most common initial clinical manifestation was peripheral precocious puberty (PPP) in 67% of patients and 75% had café-au-lait spots. Fibrous dysplasia was present in 75% of patients and the mean age at diagnosis was 7.9 ± 4.7 years. Ten patients had a bone scintigraphy, with an age at the first examination that varied between 2 and 38 years of age. The most frequent location of dysplasia was craniofacial and appendicular. No patient had a recorded history of cholestasis, hepatitis, or pancreatitis. In four patients, a genetic study was performed that was positive for the pathogenic variant of guanine nucleotide binding protein, alpha stimulating (GNAS). CONCLUSIONS: These patients demonstrate the variable nature of the clinical presentation and study of FD/MAS. It is essential to increase the index of diagnostic suspicion and adherence to international recommendations.

Pioneering studies on monogenic central precocious puberty

ABSTRACT Pubertal 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. Arch Endocrinol Metab. 2019;63(4):438-44

Implicancias del polimorfismo de repeticiones de glutamina del receptor de andrógenos en la presentación de eventos peripuberales / Implications of androgen receptor gene glutamine repeat polymorphism in the presentation of peripubertal events

Puberty is a period of transition during which girls and boys acquire secondary sexual characteristics and reproductive capacity. The order of appearance of the pubertal traits accounts for a correct or otherwise incorrect activation of the hypothalamic-pituitary-gonadal axis. The growth of the pubic hair before 8 years in girls and 9 years in boys (precocious pubarche, PP) without any other apparent cause has been largely attributed to the early increase of adrenal androgen levels. Also, premature adrenarche (PA) was traditionally considered an extreme within the normal range, however emerging evidence links early androgen excess with the metabolic syndrome. In this context, it has been suggested that an exacerbated clinical manifestation of androgens may be related to greater sensitivity of the androgen receptor (AR). The purpose of this review is to summarize the current knowledge of the contribution of the CAG repeats polymorphisms of AR in the peripubertal manifestations of androgens with special emphasis on precocious pubarche and body composition

Mutações inativadoras no gene MKRN3 são causa de puberdade precoce central familial / Inactivating mutations in the MKRN3 gene are cause of familial central precocious puberty

A maioria dos casos de puberdade precoce central (PPC) em meninas permanece idiopática. A hipótese de uma causa genética vem se fortalecendo após a descoberta de alguns genes associados a este fenótipo, sobretudo aqueles implicados com o sistema kisspeptina (KISS1 e KISS1R). Entretanto, apenas casos isolados de PPC foram relacionados à mutação na kisspeptina ou em seu receptor. Até recentemente, a maioria dos estudos genéticos em PPC buscava genes candidatos selecionados com base em modelos animais, análise genética de pacientes com hipogonadismo hipogonadotrófico, ou ainda, nos estudos de associação ampla do genoma. Neste trabalho, foi utilizado o sequenciamento exômico global, uma metodologia mais moderna de sequenciamento, para identificar variantes associadas ao fenótipo de PPC. Trinta e seis indivíduos com a forma de PPC familial (19 famílias) e 213 casos aparentemente esporádicos foram inicialmente selecionados. A forma familial foi definida pela presença de mais de um membro afetado na família. DNA genômico foi extraído dos leucócitos do sangue periférico de todos os pacientes. O estudo de sequenciamento exômico global realizado pela técnica ILLUMINA, em 40 membros de 15 famílias com PPC, identificou mutações inativadoras em um único gene, MKRN3, em cinco dessas famílias. Pesquisa de mutação no MKRN3 realizada por sequenciamento direto em duas famílias adicionais (quatro pacientes) identificou duas novas variantes nesse gene. O MKRN3 é um gene de um único éxon, localizado no cromossomo 15 em uma região crítica para a síndrome de Prader Willi. O gene MKRN3 sofre imprinting materno, sendo expresso apenas pelo alelo paterno. A descoberta de mutações em pacientes com PPC familial despertou o interesse para a pesquisa de mutações nesse gene em 213 pacientes com PPC aparentemente esporádica por meio de reação em cadeia de polimerase seguida de purificação enzimática e sequenciamento automático direto (Sanger). Três novas mutações e duas...

Most cases of central precocious puberty (CPP) in girls remain idiopathic. The hypothesis of a genetic cause has been strengthened after the discovery of some genes associated with this phenotype, particularly those involved with the kisspeptin system (KISS1 and KISS1R). However, genetic defects in KISS1 and its receptor are rare and have been identified in only a few patients with CPP.over the past years. To date, most genetic studies in CPP was based mainly on a candidate gene approach, including genes selected in animal studies, human models of patients with hypogonadotropic hypogonadism or in genome wide association studies. In the present study, we used whole exome sequencing, a more advanced method of sequencing, to identify variants associated with CPP. Thirty-six patients with the familial form of CPP (19 families) and 213 apparently sporadic cases were initially selected. The familial form was defined by the presence of more than one member affected in the family. Genomic DNA was extracted from peripheral blood leukocytes in all patients. Whole exome sequencing performed by ILLUMINA technique in 40 members of 15 families with CPP, identified inactivating mutations in a single gene, MKRN3, in five out of these families. Analysis of MKRN3 mutations performed by automatic sequencing in two additional families (four patients) identified two novel mutations. MKRN3 is an introless gene located on chromosome 15, in the Prader Willi syndrome critical region, and it is expressed only by the paternal allele due to the maternal imprinting. Following the initial findings, we searched for MKRN3 mutations in 213 patients with apparently sporadic CPP using polymerase chain reaction followed by direct enzymatic purification and automated sequencing (Sanger). Three new mutations and two previously reported, including four frameshifts and one missense variant was identified in six unrelated girls with CPP. All variants were not described in...

Mutational analysis of TAC3 and TACR3 genes in patients with idiopathic central pubertal disorders / Análise de mutações nos genes TAC3 e TACR3 em pacientes com distúrbios puberais centrais idiopáticos

OBJECTIVE: 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. Arq Bras Endocrinol Metab. 2012;56(9):646-52.

OBJETIVO: Investigar a presença de variantes nos genes TAC3 e TACR3, os quais codificam a NKB e seu receptor (NK3R), respectivamente, em uma coorte de pacientes com distúrbios puberais centrais idiopáticos. SUJEITOS E MÉTODOS: Duzentos e trinta e sete pacientes foram estudados: 114 com puberdade precoce central (PPC), 73 com hipogonadismo hipogonadotrófico isolado normósmico (HHI) e 50 com retardo constitucional do crescimento e desenvolvimento (RCCD). O grupo controle consistiu de 150 indivíduos brasileiros que apresentaram desenvolvimento puberal normal. O DNA genômico foi extraído de sangue periférico, e as regiões codificadoras dos genes TAC3 e TACR3 foram amplificadas e sequenciadas automaticamente. RESULTADOS: Uma variante (p.A63P) foi identificada na NKB, e quatro variantes, p.G18D, p.L58L (c.172C>T), p.W275X e p.A449S, foram identificadas no NK3R, as quais foram ausentes no grupo controle. A variante p.A63P foi identificada em uma menina com PPC, e a variante p.A449S, em uma menina com RCCD. As variantes previamente descritas, p.G18D, p.L58L e p.W275X, foram identificadas em três indivíduos com HHI normósmico do sexo masculino não relacionados. CONCLUSÃO: Variantes raras nos genes TAC3 e TACR3 foram identificadas em pacientes com distúrbios puberais centrais idiopáticos. Mutações de perda de função no gene TACR3 foram associadas com o fenótipo de HHI normósmico. Arq Bras Endocrinol Metab. 2012;56(9):646-52.

Clinical and molecular aspects of a pediatric metachronous adrenocortical tumor / Aspectos clínicos e moleculares de tumor adrenocortical metacrônico pediátrico

The occurrence of metachronous adrenocortical carcinoma has rarely been described. We report a case of a child with virilizing adrenocortical metachronous tumors that, despite several metastases, presented long-term survival (15 years). We analyzed in this tumor IGF2, IGF1R and FGFR4 gene expression, and evaluated the presence of p.R337H germline p53 mutation and somatic CTNNB1 mutation. IGF2 gene was over-expressed in both left (Weiss score 5) and right (Weiss 7) adrenocortical tumors. IGF1R expression levels were higher in the right adrenocortical tumor. FGFR4 over-expression was also detected in the right adrenocortical tumor. In addition, this patient harbors the germline p.R337H p53 mutation and loss of heterozygosity (LOH) was detected in the tumors. No somatic CTNNB1 mutations were found in both tumors. In conclusion, we demonstrated in this unusual case the over-expression of growth signaling pathways, which are molecular mechanisms previously related to adrenocortical tumorigenesis. Furthermore, the absence of somatic CTNNB1 mutations, which is a molecular marker of poor prognosis in adults, might be related to the long-term survival of this patient.

A ocorrência de carcinomas adrenocorticais metacrônicos é raramente relatada. Descrevemos o caso de uma criança portadora de tumor adrenocortical virilizante metacrônico que, apesar das inúmeras metástases, apresentou uma longa sobrevida (15 anos). Analisamos nesse tumor a expressão gênica de IGF2, IGF1R e FGFR4 e avaliamos a presença da mutação germinativa R337H no p53 e mutação somática no gene CTNNB1. O gene IGF2 foi hiperexpresso nos tumores adrenocorticais esquerdo (Weiss 5) e direito (Weiss 7). Os níveis de expressão de IGF1R foram maiores no tumor direito. Hiperexpressão do gene FGFR4 também foi observada no tumor adrenocortical direito. Esse paciente é portador da mutação germinativa R337H no p53, e perda de heterozigose (LOH) foi observada em ambos os tumores. Não foram encontradas mutações no gene CTNNB1 nos tumores. Em conclusão, demonstramos neste caso a hiperexpressão de vias moleculares de crescimento, que são mecanismos previamente relacionados à tumorigênese adrenocortical. Além disso, não encontramos mutações somáticas no gene CTNNB1, que é um marcador molecular de mau prognóstico em adultos e poderia estar relacionado à longa sobrevida desse paciente.

Triagem de mutações nos receptores de Angiotensina II, AGTR1 e AGTR2 e avaliação dos polimorfismos C573T e A1166C do gene AGTR1 em pacientes com adrenarca precoce idiopática / Mutation screening in Angiotensin II receptors, AGTR1 and AGTR2, and evaluation of AGTR1 polymorphisms C573T and A1166C in patients with premature adrenarche / Mutation screening in Angiotensin II receptors, AGTR1 and AGTR2, and evaluation of AGTR1 polymorphisms C573T and A1166C in patients with premature adrenarche

Pubarca precoce é o aparecimento de pêlos pubianos antes dos 8 anos em meninas e 9 anos em meninos, sendo sua etiologia mais freqüente a adrenarca precoce idiopática, a longo prazo, associada à síndrome metabólica. Dentre os fatores envolvidos na gênese da adrenarca precoce podemos citar a Angiotensina II (Ang II), a qual promove proliferação celular e esteroidogênese, podendo agir através de dois receptores, o tipo 1 (AT1) e o tipo 2 (AT2). Com o intuito de estudar mutações dos genes dos receptores da AngII, foram avaliadas 50 crianças com diagnóstico de adrenarca precoce idiopática e comparadas ao grupo controle de indivíduos normais. Não foram detectadas mutações dos genes AGTR1 e AGTR2, contudo dois polimorfismos foram identificados no gene AGTR1: o polimorfismo C573T (localizado no exon 5) e o A1166C (na região 3' não codificadora). A freqüência do alelo polimórfico T573 foi de 35 por cento nos pacientes e 38 por cento nos controles. O alelo polimórfico C1166 esteve presente em 24 por cento dos pacientes e em 26 por cento dos controles. Não houve diferença significante entre os grupos, assim como não houve correlação entre a freqüência dos polimorfismos C573T e A1166C e as variáveis clínicas e laboratoriais dos pacientes, ou com sua história familial de síndrome metabólica.

Precocious pubarche is the appearance of pubic hair before the age of 8 years in girls and 9 years in boys. The most frequent etiology is idiopathic precocious adrenarche, suggested, after long-term follow-up, to be associated with metabolic syndrome. One of the factors involved in the genesis of precocious adrenarche is Angiotensin II (Ang II), which promotes cell proliferation and steroidogenesis through type 1 (AT1) and type 2 (AT2) receptors. In order to study Ang II receptors mutations, 50 children with idiopathic precocious adrenarche were evaluated and compared to a control group of normal individuals. Mutations were not detected in the AGTR1 and AGTR2 genes; however, two polymorphisms were identified in the AGTR1 gene: the C573T (exon 5) and the A1166C (3' untranslated region). The polymorphic allele T573 was found in 35 percent of the patients and 38 percent of controls. The polymorphic allele C1166 was present in 24 percent of the patients and 26 percent of controls. There was no statistical difference between groups. There was also no correlation between the polymorphisms and clinical and laboratory findings, as well as their family history of metabolic syndrome.

Polysyndactyly, gelastic seizures, hypothalamic hamartoma and precocious puberty - a variant of Pallister-Hall syndrome?

Os autores relatam o caso de uma menina portadora de polissindactilia, que apresenta crises gelásticas desde o período neonatal. Aos dois anos de idade, foi detectada, através da ressonância magnética, lesäo hipotalâmica sugestiva de hamartoma. Logo após, a partir do surgimento de pelos pubianos, foi diagnosticada puberdade precoce. As características mencionadas sugerem tratar-se de uma variante da síndrome de Pallister-Hall. A conduta terapêutica tem sido conservadora, apesar da resposta pobre aos anticonvulsivantes.