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Marui S.,Laboratorio Of Hormonios E Genetica Molecular Lim
Hormone Research in Paediatrics | Year: 2012

Background: Mutations in GH-releasing hormone receptor gene (GHRHR) are emerging as the most common cause of autosomal recessive isolated GH deficiency (IGHD). Objective: To search for GHRHR mutations in patients with familial or sporadic IGHD and to investigate founder effects in recurring mutations. Methods: The coding region of GHRHR was entirely amplified and sequenced from DNA of 18 patients with IGHD (16 unrelated) with topic posterior pituitary lobe on MRI. Haplotypes containing promoter SNPs and microsatellites flanking GHRHR were analyzed in patients with c.57+1G>A (IVS1+1G>A) mutation of our previously published kindred and also a Brazilian patient and 2 previously reported Japanese sisters with c.1146G>A (p.E382E) mutation. Results: A novel homozygous intronic GHRHR c.752-1G>A (IVS7-1G>A) mutation, predicting loss of the constitutive splice acceptor site, was identified in two siblings with IGHD. A compound heterozygous c.[57+1G>A];[1146G>A] and a heterozygous c.527C>T (p.A176V) were found in two sporadic cases. Haplotype analysis provided evidence for a founder effect for the c.57+1G>A mutation and independent recurrence for the c.1146G>A mutation. Conclusion: We report a novel splice-disrupting mutation in GHRHR in 2 siblings and provide evidence that all c.57+1G>A (IVS1+1G>A) mutant chromosomes have the same haplotype ancestor, indicating the occurrence of a founder effect in Brazilian patients with IGHD. Copyright © 2012 S. Karger AG, Basel. Source


Ribeiro T.C.,Laboratorio Of Hormonios E Genetica Molecular Lim | Jorge A.A.,Laboratorio Of Hormonios E Genetica Molecular Lim42 | Almeida M.Q.,University of Sao Paulo | Mariani B.M.D.P.,Laboratorio Of Hormonios E Genetica Molecular Lim | And 4 more authors.
BioMed Research International | Year: 2014

Context. IGF1R overexpression appears to be a prognostic biomarker of metastatic pediatric adrenocortical tumors. However, the molecular mechanisms that are implicated in its upregulation remain unknown. Aim. To investigate the potential mechanisms involved in IGF1R overexpression. Patients and Methods. We studied 64 adrenocortical tumors. IGF1R copy number variation was determined in all patients using MLPA and confirmed using real time PCR. In a subgroup of 32 patients, automatic sequencing was used to identify IGF1R allelic variants and the expression of microRNAs involved in IGF1R regulation by real time PCR. Results. IGF1R amplification was detected in an adrenocortical carcinoma that was diagnosed in a 46-year-old woman with Cushing's syndrome and virilization. IGF1R overexpression was demonstrated in this case. In addition, gene amplification of other loci was identified in this adrenocortical malignant tumor, but no IGF1R copy number variation was evidenced in the remaining cases. Automatic sequencing revealed three known polymorphisms but they did not correlate with its expression. Expression of miR-100, miR-145, miR-375, and miR-126 did not correlate with IGF1R expression. Conclusion. We demonstrated amplification and overexpression of IGF1R gene in only one adrenocortical carcinoma, suggesting that these combined events are uncommon. In addition, IGF1R polymorphisms and abnormal microRNA expression did not correlate with IGF1R upregulation in adrenocortical tumors. © 2014 Tamaya Castro Ribeiro et al. Source

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