Teresa C. Vieira

Mutations linked to familial hypokalaemic periodic paralysis in the calcium channel α1 subunit gene (Cav1·1) are not associated with thyrotoxic hypokalaemic periodic paralysis

objective To investigate whether patients with thyrotoxic hypokalaemic periodic paralysis (THPP) have the same molecular defect in the calcium channel gene described in familial hypokalaemic periodic paralysis (FHPP), as the symptoms of both diseases are comparable, we analysed, in patients with THPP, the presence of mutations R528H, R1239H and R1239G on the S4 voltage‐sensing transmembrane segment of the α1 subunit of the calcium channel gene (Cav1·1).

Molecular analysis of PROP1, PIT1, HESX1, LHX3, and LHX4 shows high frequency of PROP1 mutations in patients with familial forms of combined pituitary hormone deficiency

UNLABELLED Combined Pituitary Hormone Deficiency (CPHD) is a prevalent disease in Neuroendocrinology services. The genetic form of CPHD may originate from mutations in pituitary transcription factor (PTF) genes and the pituitary image in these cases may give a clue of what PTF is most probably mutated: defects in LHX4 are usually associated with ectopic posterior pituitary (EPP); defects in LHX3, PIT1, and PROP1, with normally placed posterior pituitary (NPPP); HESX1 mutations are associated with both. OBJECTIVE To identify mutations in PTF genes in patients with idiopathic hypopituitarism followed in our service, based on the presence or absence of EPP on sellar MRI. METHODS Forty patients with idiopathic hypopituitarism (36 families, 9 consanguineous), followed in the Neuroendocrinology Outpatient Clinic of UNIFESP, Brazil, were submitted to sequencing analyses of PTF genes as follows: LHX3, HESX1, PIT1, and PROP1 were sequenced in patients with NPPP (26/40) and HESX1 and LHX4 in patients with EPP (14/40). RESULTS We identified only PROP1 mutations in 9 out of 26 patients with CPHD and NPPP (35%). Since eight of them came from 4 consanguineous families, the prevalence of PROP1 mutations was higher when only consanguineous families were considered (44%, 4/9). At the end of the study, we decided to sequence PROP1 in patients with EPP, just to confirm that they were not candidates for PROP1 mutations. No patients with EPP had PROP1 or other PTF mutations. CONCLUSIONS Patients with idiopathic CPHD and NPPP, born from consanguineous parents, are the strong candidates for PROP1 mutations. Other developmental gene(s) may be involved in the genesis of idiopathic hypopituitarism associated with EPP.

Hereditary corticosteroid-binding globulin deficiency due to a missense mutation (Asp367Asn, CBG Lyon) in a Brazilian kindred

objective Abnormal corticosteroid‐binding globulin (CBG) is an extremely rare condition and only three mutations have been described in four families. The molecular basis of an abnormal CBG in a Brazilian family was studied and correlations between genotype and serum cortisol, cortisol binding capacity (CBC) and CBG levels were determined.

The natural history of the R120C PROP1 mutation reveals a wide phenotypic variability in two untreated adult brothers with combined pituitary hormone deficiency

Background: Combined pituitary hormone deficiency (CPHD) corresponds to impaired production of growth hormone (GH) and other anterior pituitary hormones. The genetic form of CPHD may result from mutations in pituitary transcription factor genes, and PROP is the most commonly mutated gene in these cases. Patients with PROP1 mutations may have variable CPHD phenotypes but, because they are usually treated in childhood, the wide phenotypic variability caused by these mutations may not be thoroughly appreciated. Methods: Clinical follow-up and molecular analysis of PROP1 in two adult brothers with CPHD, born from consaguineous parents, and not treated until late adulthood. Results: The homozygous R120C mutation was identified in the brothers. Their clinical follow-up showed a wide phenotypic variability: hypogonadism was severe and prevented pubertal development in both, but their final heights were remarkably different, pointing to different degrees in severity of GH/TSH deficiencies; cortisol deficiency developed late in both, but at least 10 yr apart. Conclusion: The lack of treatment in childhood and adolescence allowed the appreciation of the entire natural history of the CPHD caused by the R120C mutation, and it revealed a remarkable phenotypic variability even in siblings with a very similar genetic background.

Hyperinsulinemic hypoglycemia evolving to gestational diabetes and diabetes mellitus in a family carrying the inactivating ABCC8 E1506K mutation

Vieira TC, Bergamin CS, Gurgel LC, Moisés RS. Hyperinsulinemic hypoglycemia evolving to gestational diabetes and diabetes mellitus in a family carrying the inactivating ABCC8 E1506K mutation.

Absence of activating mutations in the hot spots of the LH receptor and Gs-α genes in Leydig cell tumors

Leydig-cell tumors are functioning endocrine tumors that produce T autonomously leading to isosexual precocity in boys and virilization in female patients. Molecular abnormalities such as activating mutations of the luteinizing hormone receptor (LHR), a G protein-coupled receptor, and of the Gs-α subunit of G protein have recently been described in these tumors. Both mutations cause continuous activation of the cAMP signaling cascade, autonomous production of T and cell proliferation. We searched for activating mutations in exon 11 of the LHR gene and in exons 8 and 9 of the Gs-a gene, which contain all hot spots for those mutations, in 4 Leydig cell tumors obtained from 4 patients (one boy with LH-independent precocious puberty and 3 women with virilization). DNA was extracted from paraffin-embedded neoplastic and non-neoplastic tissues and from peripheral lymphocytes. Hot spot regions of exons 11 of LHR and exons 8 and 9 of Gs-a genes were amplified by PCR and the purified PCR products were directly sequenced. No LHR or Gs-a gene mutations were found in the 4 tumors studied. Considering the previously reported mutations found in Leydig cell tumors, the absence of activating mutations in the hot spot regions for activating mutations in these tumors indicate molecular heterogeneity among Leydig cell tumors.

Central precocious puberty associated with pituitary duplication and midline defects.

Central precocious puberty (CPP) is due to premature activation of the hypothalamic-pituitary-gonadal axis. It may be idiopathic or result from congenital or acquired CNS lesions. We describe a 7.4 year-old Brazilian girl with CPP who also presented hypertelorism, limitation of lateral neck rotation and synkinesis of the hands. Sellar and cervical column MRIs revealed pituitary duplication and rudimentary intervertebral disks. We present the clinical and imaging observations of this case, and a thorough literature review of this rare developmental abnormality.

Children with Cushing’s syndrome: primary pigmented nodular adrenocortical disease should always be suspected

Primary Pigmented Nodular Adrenocortical Disease (PPNAD) is a rare form of bilateral adrenocortical hyperplasia that is inherited in an autosomal dominant manner and leads to ACTH-independent Cushing’s syndrome (CS). PPNAD may be isolated or associated with Carney Complex (CNC). For the diagnosis of PPNAD and CNC, in addition to the hormonal and imaging tests, searching for PRKAR1A mutations may be recommended. The aims of the present study are to discuss the clinical and molecular findings of two Brazilian patients with ACTH-independent CS due to PPNAD and to show the diagnostic challenge CS represents in childhood. Description of two patients with CS and the many sequential steps for the diagnosis of PPNAD is provided. Sequencing analysis of all coding exons of PRKAR1A in the blood, frozen adrenal nodules (patients 1 and 2) and testicular tumor (patient 1) is performed. After several clinical and laboratory drawbacks that misled the diagnostic investigation in both patients, the diagnosis of PPNAD was finally established and confirmed through pathology and molecular studies. In patient 1, sequencing of PRKAR1A gene revealed a novel heterozygous 10-bp deletion in exon 3, present in his blood, adrenal gland and testicular tumor. The etiologic diagnosis of endogenous CS in children is a challenge that requires expertise and a multidisciplinary collaboration for its prompt and correct management. Although rare, PPNAD should always be considered among the possible etiologies of CS, due to the high prevalence of this disease in this age group.

Terapia de reposição hormonal no hipopituitarismo

This article brings an updated review of hypopituitarism with emphasis in hormone replacement therapy. The physiological basis of hormone replacement therapy and practical aspects of treating hypopituitary patients were both taken into account to provide a rational strategy for treatment. The review is organized by individual pituitary hormone deficiency and covers epidemiology, etiology, clinical presentation, and diagnosis of hypopituitarism, as well as the most relevant hormone preparations currently available for treating each hormone deficiency. Practical guidelines to hormone dosing, routes of administration, side effects and clinical and laboratory monitoring during the entire lifespan are given for each individual hormone replacement therapy: growth hormone in GH-deficient children and adults, thyroid hormone in central hypothyroidism, glucocorticoid in central hypoadrenalism, vasopressin analogs in diabetes insipidus, sex hormones in man and women from puberty to senescence, and gonadotropins for treating infertility. In addition to the literature review, we took into account our own experience of more than two decades in investigating, diagnosing, and treating hypopituitary patients at the Universidade Federal de Sao Paulo.