[Show abstract][Hide abstract] ABSTRACT: We report a case of adrenal hypoplasia congenita (AHC) and hypogonadotropic hypogonadism (HH) due to a novel DAX1 mutation. A 19-month-old boy with hyperpigmentation and failure to thrive came to our service for investigation. Three brothers of the patient had died due to adrenal failure, and a maternal cousin had adrenal insufficiency. Adrenoleukodystrophy was excluded. MRI showed normal pituitary and hypothalamus. Plasma hormone evaluation revealed high ACTH (up to 2,790 pg/mL), and low levels of androstenedione, DHEA-S, 11-deoxycortisol, and cortisol. At 14 years of age the patient was still prepubescent, his weight was 43.6 kg (SDS: -0.87) and his height was 161 cm (SDS: -0.36), with normal body proportions. In the GnRH test, basal and maximum values of LH and FSH were respectively 0.6/2.1 and < 1.0/< 1.0 U/L. Molecular investigation identified a novel mutation that consists of a deletion of codon 372 (AAC; asparagine) in exon 1 of DAX1. This mutation was not found in a study of 200 alleles from normal individuals. Prediction site analysis indicated that this alteration, located in the DAX1 ligand-binding domain, may damage DAX1 protein. We hypothesize that the novel (p.Asp372del) DAX1 mutation might be able to cause a disruption of DAX1 function, and is probably involved in the development of AHC and HH in this patient. Arq Bras Endocrinol Metab. 2012;56(8):496-500.
Arquivos brasileiros de endocrinologia e metabologia 11/2012; 56(8):496-500. · 0.68 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Metabolic syndrome (MS) has been a condition involved in considerable controversy, starting with the terminology. Gerald Reaven himself, the author who proposed the term MS, advised against the use of this terminology because the definition implies in at least three metabolic alterations, and it is never clear to which group of alterations we are referring to when we say that a patient has MS. In children, the problem is even more complicated, since there are many different adaptations to the criteria used in adults. On the other hand, independent of the terminology, cardiovascular risks are well-established and it is very clear that even children may present metabolic disturbances which predict future metabolic problems. The role of the pediatric endocrinologist or the general pediatrician is to investigate, especially in overweight/obese children, conditions that if treated early, may prevent future complications that today, unfortunately, are being diagnosed only in adult life. In this review, we discuss problems on the definition, epidemiology, pathophysiology, and complications of MS in children and adolescents.
Arquivos brasileiros de endocrinologia e metabologia 11/2011; 55(8):576-82. · 0.68 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: MCT8 is a cellular transporter of thyroid hormones important in their action and metabolization. We report a male patient with the novel inactivating mutation 630insG in the coding region in exon 1 of MCT8. He was characterized clinically by severe neurologic impairment (initially with global hypotonia, later evolving with generalized hypertonia), normal growth during infancy, reduced weight gain, and absence of typical signs and symptoms of hypothyroidism, while the laboratory evaluation disclosed elevated T3, low total and free T4, and mildly elevated TSH serum levels. Treatment with levothyroxine improved thyroid hormone profile but was not able to alter the clinical picture of the patient. These data reinforce the concept that the role of MCT8 is tissue-dependent: while neurons are highly dependent on MCT8, bone tissue, adipose tissue, muscle, and liver are less dependent on MCT8 and, therefore, may suffer the consequences of the exposition to high serum T3 levels.
Arquivos brasileiros de endocrinologia e metabologia 02/2011; 55(1):60-6. · 0.68 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: To describe the presence of prostatic tissue in 46,XX patients with the classical form of congenital adrenal hyperplasia (CAH); to evaluate the sensitivity and specificity of prostatic specific antigen (PSA) measured in congenital adrenal hyperplasia patients with regard to the detection of prostatic tissue in pelvic MRI.
We studied 52 children and adolescents, 32 with the classical form of congenital adrenal hyperplasia, 10 boys and 10 girls without CAH. Pelvic MRI was performed in all patients to detect prostatic tissue. Prostate specific antigen, testosterone and dihydrotestosterone were measured in all patients. We used Receiver Operating Characteristic Curve for PSA discrimination capacity.
Five girls with congenital adrenal hyperplasia showed image of prostatic tissue on pelvic MRI. Prostate specific antigen showed sensitivity and specificity of 100% and 88.9%, respectively, taking 0.1 ng/mL as the cutoff level.
The incidence of prostatic tissue in 46,XX patients with the classical form of congenital adrenal hyperplasia was 15.6%. PSA demonstrated to be a good marker of prostatic tissue in these patients and should be used to screen patients to be submitted to image studies.
Arquivos brasileiros de endocrinologia e metabologia 08/2009; 53(6):716-20. · 0.68 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The hypophosphatemic conditions that interfere in bone mineralization comprise many hereditary or acquired diseases, all of them sharing the same pathophysiologic mechanism: reduction in the phosphate reabsorption by the renal tubuli. This process leads to chronic hyperphosphaturia and hypophosphatemia, associated with inappropriately normal or low levels of calcitriol, causing osteomalacia or rickets in children and osteomalacia in adults. X-linked hypophosphatemic rickets, autosomal-dominant hypophosphatemic rickets, and tumor-induced osteomalacia are the main syndromes involved in the hypophosphatemic rickets. Although these conditions exhibit different etiologies, there is a common link among them: increased activity of a phosphaturic factor, being the fibroblast growth factor 23 (FGF-23) the most studied one and to which is attributed a central role in the pathophysiology of the hyperphosphaturic disturbances. Activating mutations of FGF-23 and inactivating mutations in the PHEX gene (a gene on the X chromosome that codes for a Zn-metaloendopeptidase proteolytic enzyme which regulates the phosphate) involved in the regulation of FGF-23 have been identified and have been implicated in the pathogenesis of these disturbances. Genetic studies tend to show that the phosphorus homeostasis depends on a complex osteo-renal metabolic axis, whose mechanisms of interaction have been poorly understood so far. This paper reviews the current knowledge status concerning the pathophysiology of phosphate metabolism regulation and the pathophysiologic basis of hypophosphatemic rickets. It also analyzes the clinical picture and the therapeutic aspects of these conditions as well.
[Show abstract][Hide abstract] ABSTRACT: We studied the growth hormone receptor (GHR) gene in 6 patients with Laron syndrome (LS) from 4 unrelated families. Exons 2 to 10 were amplified by PCR using specific intronic pairs of primers. The PCR products were directly sequenced. Our results showed that all 6 patients carried a homozygous GAG>GAA mutation in codon 180 of exon 6. This mutation did not change the translated amino acid, but created an abnormal splice site deleting 8 amino acids from the extracellular domain of GHR. Members of all 4 kindreds with the E180splice mutation were genotyped for 4 polymorphic intragenic sites: The retention or exclusion of exon 3, single nucleotide polymorphisms present in exons 6 and 10, and intron 9 polymorphic site. All 6 patients presented the same haplotype. The E180splice mutation was first described in a population of Spanish descendants from the Andes of Southern Ecuador. This mutation was also found in oriental Jewish patients from Israel. Our families share the same intron-9 haplotype observed in Ecuadorian and Israeli patients. We conclude that the E180splice mutation is an important cause of LS in Brazil and there is probably a founder effect since our patients, Ecuadorian and Israeli patients share the same haplotype in intron 9.
[Show abstract][Hide abstract] ABSTRACT: Familial hypocalciuric hypercalcemia (FHH) and neonatal severe hyperparathyroidism (NSHPT) are consequent to inactivating mutations of the calcium-sensing receptor (CaR) gene. FHH is usually associated with heterozygous inactivating mutations of the CaR gene, whereas NSHPT is usually due to homozygous inactivation of the CaR gene. FHH is generally asymptomatic and is characterized by mild to moderate lifelong hypercalcemia, relative hypocalciuria, and normal intact PTH, whereas individuals with NSHPT frequently show life-threatening hypercalcemia. In this study, we report a novel inactivating mutation of the CaR gene, identified in a 9-yr-old Brazilian girl who was found to be severely hypercalcemic during investigation of a 6-month history of headaches and vomits. Direct sequencing of the CaR gene from this patient showed a novel homozygous mutation (L13P) in exon 2. Functional characterization by intracellular calcium measurement by fluorometry showed that the mutant receptor had a dose-response curve shifted to the right relative to that of wild type. The proband's consanguineous parents, who had mild asymptomatic hypercalcemia, showed the same mutation in the heterozygous form. The mutation described in this study is the inactivating missense mutation present at the most N-terminal end among the known CaR missense mutations. This study reinforces the fact that patients with homozygous inactivation of the CaR gene may present with severe hypercalcemia in different phases of life.