Germline mutation analysis of Tpit in Poodle dogs with ACTH-dependent hyperadrenocorticism / Análise de mutação germinativa do Tpit em cães da raça Poodle com hiperadrenocorticismo ACTH-dependente

There is a high incidence of pituitary-dependent hyperadrenocorticism (PDH) in Poodle dogs, with family members being affected by the disease, suggesting a genetic involvement. Tpit is an obligate transcription factor for the expression of pro-opiomelanocortingene and for corticotroph terminal differentiation. The aim of the present study was to screen the Tpit gene for germline mutations in Poodles with PDH. Fifty Poodle dogs (33 female, 8.71±2.8 years) with PDH and 50 healthy Poodle dogs (32 females, 9.4241 2.8 years) were studied. Genomic DNA was isolated from peripheral blood, amplified by PCR and submitted to automatic sequence. No mutation in the coding region of Tpit was found, whereas the new single nucleotide polymorphism p.S343G, in heterozygous state, was found in the same frequency in both PDH and control groups. We concluded that Tpit gain-of-function mutations are not involved in the etiology of PDH in Poodle dogs.

O hiperadrenocorticismo ACTH-dependente (HACAD) apresenta elevada incidência em cães da raça Poodle, sendo que membros da mesma família têm sido acometidos pela doença, sugerindo envolvimento genético. Tpit é um fator de transcrição obrigatório para a expressão do gene da pro-opiomelanocortina e para a diferenciação terminal dos corticotrofos. O objetivo deste trabalho foi pesquisar mutações germinativas no gene Tpit em Poodles com HACAD. Cinquenta cães da raça Poodle, 33 fêmeas, média de idade de 8,71±2,8 anos, com HACAD, e 50 cães Poodles saudáveis, 32 fêmeas, média de idade de 9,4±2,8 anos, foram estudados. Mutações na região codificadora do gene Tpit não foram identificadas. Foi observado um novo polimorfismo em heterozigose, p.S343G, com a mesma frequência no grupo de cães com HACAD e no grupo-controle. Conclui-se que a mutação ativadora no gene Tpit não está envolvida na patogênese do hiperadrenocorticismo ACTH-dependente em cães da raça Poodle.

Mutations in the SRY, DAX1, SF1 and WNT4 genes in Brazilian sex-reversed patients

In most mammals, male development is triggered by the transient expression of the SRY gene, which initiates a cascade of gene interactions ultimately leading to the formation of a testis from the indifferent fetal gonad. Mutation studies have identified several genes essential for early gonadal development. We report here a molecular study of the SRY, DAX1, SF1 and WNT4 genes, mainly involved in sexual determination, in Brazilian 46,XX and 46,XY sex-reversed patients. The group of 46,XX sex-reversed patients consisted of thirteen 46,XX true hermaphrodites and four 46,XX males, and was examined for the presence of the SRY gene and for the loss of function (inactivating mutations and deletions) of DAX1 and WNT4 genes. In the second group consisting of thirty-three 46,XY sex-reversed patients we investigated the presence of inactivating mutations in the SRY and SF1 genes as well as the overexpression (duplication) of the DAX1 and WNT4 genes. The SRY gene was present in two 46,XX male patients and in none of the true hermaphrodites. Only one mutation, located outside homeobox domain of the 5' region of the HMG box of SRY (S18N), was identified in a patient with 46,XY sex reversal. A novel 8-bp microdeletion of the SF1 gene was identified in a 46,XY sex-reversed patient without adrenal insufficiency. The dosage of DAX1 and WNT4 was normal in the sex-reversed patients studied. We conclude that these genes are rarely involved in the etiology of male gonadal development in sex-reversed patients, a fact suggesting the presence of other genes in the sex determination cascade

Clinical and molecular analysis of human reproductive disorders in Brazilian patients

Several genes that influence the development and function of the hypothalamic-pituitary-gonadal-axis (HPG) have been identified. These genes encode an array of transcription factors, matrix proteins, hormones, receptors, and enzymes that are expressed at multiple levels of the HPG. We report the experience of a single Endocrinology Unit in the identification and characterization of naturally occurring mutations in families affected by HPG disorders, including forms of precocious puberty, hypogonadism and abnormal sexual development due to impaired gonadotropin function. Eight distinct genes implicated in HPG function were studied: KAL, SF1, DAX1, GnRH, GnRHR, FSHá, FSHR, and LHR. Most mutations identified in our cohort are described for the first time in literature. New mutations in SF1, DAX1 and GnRHR genes were identified in three Brazilian patients with hypogonadism. Eight boys with luteinizing hormone- (LH) independent precocious puberty due to testotoxicosis were studied, and all have their LH receptor (LHR) defects elucidated. Among the identified LHR molecular defects, three were new activating mutations. In addition, these mutations were frequently associated with new clinical and hormonal aspects, contributing significantly to the knowledge of the molecular basis of reproductive disorders. In conclusion, the naturally occurring genetic mutations described in the Brazilian families studied provide important insights into the regulation of the HPG.

Hyperandrogenism due to 3 beta-hydroxysteroid dehydrogenase deficiency with accessory adrenocortical tissue: a hormonal and metabolic evaluation

1. Adrenal ectopic tissue has been detected in the paragonadal region of normal women. In patients with congenital adrenal hyperplasia due to 21-hydroxylase (21-OH) deficiency, the manifestation of hyperplasia of paragonadal accessory adrenal tissue has been usually reported to occur in males. Probably, this is the first report of a female with 3 beta-hydroxysteroid dehydrogenase (3 beta-HSD) deficiency with ectopic adrenal tissue in ovaries. However, the occurrence of hyperplasia of adrenal rests among women with classical congenital adrenal hyperplasia may not be rare, especially among patients with a late diagnosis. 2. We report a woman with 3 beta-HSD deficiency whose definitive diagnosis was made late at 41 years of age immediately before surgery for the removal of a uterine myoma. During surgery, exploration of the abdominal cavity revealed the presence of bilateral accessory adrenal tissue in the ovaries and in the para-aortic region. The patient had extremely high levels of ACTH (137 pmol/l), DHEA (901.0 nmol/l), DHEA-S (55.9 mumol/l), androstenedione (70.2 nmol/l), testosterone (23.0 nmol/l) and 17 alpha-hydroxypregnenolone (234.4 nmol/l) suggesting 3 beta-HSD deficiency. 3. In view of these elevated androgen levels, with an absolute predominance of DHEA and DHEA-S, we evaluated the effect of this hormonal profile on carbohydrate tolerance and insulin response to glucose ingestion. 4. The patient presented normal glucose tolerance but her insulin response was lower than that of 14 normal women (area under the curve, 3 beta-HSD = 17,680 vs 50,034 pmol/l for the control group over a period of 3 h after glucose ingestion).(ABSTRACT TRUNCATED AT 250 WORDS)

Estudo clinico, citogenetico, histologico e da regulacao hormonal em dois casos de hermafroditismo verdadeiro. / Clinical, cytogenetic, hystological and hormonal regulation studies in 2 cases of true hermaphroditism

Foi realizado estudo clinico, citogenetico histologico e da secrecao hormonal em dois casos de hermafroditismo verdadeiro (HV).O primeiro paciente apresentava cariotipo XX e o segundo XX/XY, sendo os dois antigeno HY positivo. O exame histologico revelou ovotestis no primeiro caso com presenca de espermatogonias ate agora nao descritas no HV. O segundo paciente apresentava ovario histologicamente normal e testiculo com areas de hialinizacao tubular. A avaliacao hormonal no paciente 1 revelou grandes flutuacoes dos niveis de LH, FSH, estradiol e progesterona. Os dois pacientes apresentavam baixa resposta testicular ao estimulo com gonadotrofina corionica e liberacao de LH apos uso de estrogeno semelhante a observada no ser feminino.O citrato de clomifeno induziu resposta ovulatoria no caso testado, podendo ser utilizado na identificacao da presenca de ovotestis em caso de suspeita de HV

Identificacao da origem de metastases de carcinoma da tiroide atraves do metodo da imunoperoxidase. / Identification of the origin of metastatic carcinoma by immunoperoxidase method

Muitas vezes e dificil caracterizar a origem tiroidea a partir de tumores metastaticos. Os autores apresentam tres casos de carcinoma de tiroide com deteccao de tiroglobulina em biopsias de metastases pelvicas (casos 1 e 2) e ganglios mediastinais e supraclaviculares (caso 3) mediante imunoperoxidase. Este metodo demonstrou ser de grande utilidade na indicacao da origem tiroidea das metastases, principalmente no caso 1, no qual a metastase folicular apresentava aspecto semelhante a sarcoma alveolar de partes moles, e no caso 3, no qual a palpacao da tiroide, a cintilografia e a tiroglobulina serica foram normai

X-chromatin evaluated by Feulgen's stain method in congenital virilizing adrenal hyperplasia.

A frequencia de cromatina sexual na mucosa oral foi investigada em 11 pacientes do sexo feminino com hiperplasia congenita das supra-renais devido a deficiencia da 21-hidroxilase, forma virilizante simples.Usou-se o metodo de Feulgen para a coloracao. Demonstrou-se uma reducao da frequencia da cromatina sexual oral nestes pacientes em relacao a um grupo de mulheres normais (13,6 +/- 2,2% - 17,9 +/- 0,8% X +/- EPM). Apos 4-5 semanas de terapia com glicocorticoide, nao se observou diferenca estatisticamente significativa entre os grupos estudados (17,1 +/- 2,0%). O cariotipo realizado em 8 dos 11 casos estudados mostrou padrao feminino normal. Estas variacoes da frequencia da cromatina sexual poderiam estar relacionadas com o tamanho nuclear medio da populacao celular estudada