Mutação nova do gene MCT8 em menino Brasileiro com resistência ao hormônio tireioidiano e neuropatia grave

O MCT8 é um transportador celular de hormônios tireoidianos, importante para sua ação e metabolização. Relatamos o caso de um menino com a nova mutação inativadora 630insG no éxon 1 do MCT8. O paciente caracterizou-se por grave comprometimento neurológico (inicialmente com hipotonia global, evoluindo com hipertonia generalizada), crescimento normal nos dois primeiros anos de vida, reduzido ganho ponderal e ausência dos sinais e sintomas típicos de hipotireoidismo. A sua avaliação sérica revelou elevação do T3, redução do T4 total e livre e TSH levemente aumentado. O tratamento com levotiroxina melhorou o perfil hormonal tireoidiano, mas não modificou o quadro clínico do paciente. Esses dados reforçam o conceito de que o papel do MCT8 é tecido-dependente: enquanto os neurônios são altamente dependentes do MCT8, o osso, o tecido adiposo, o músculo e o fígado são menos dependentes do MCT8 e, portanto, podem sofrer as consequências da exposição a níveis séricos elevados de T3.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

Search of prostatic tissue in 46,XX congenital adrenal hyperplasia

OBJETIVOS: Verificar a ocorrência de tecido prostático em pacientes portadoras da forma clássica de hiperplasia congênita das suprarrenais, com cariótipo 46,XX e analisar a sensibilidade e a especificidade do antígeno prostático específico (PSA) das pacientes com hiperplasia congênita das suprarrenais em relação à detecção de tecido prostático na ressonância magnética (RNM) de região pélvica. MÉTODOS: Foram estudadas 52 crianças e adolescentes, sendo 32 meninas portadoras da forma clássica de hiperplasia congênita das suprarrenais, 10 meninas e 10 meninos sem hiperplasia congênita das suprarrenais. A RNM da região pélvica e a coleta de PSA, diidrotestosterona e testosterona foram realizadas em todos os pacientes. Para analisar a capacidade de discriminação do antígeno prostático-específico, foi utilizada a curva ROC (receiver operating characteristic curve). RESULTADOS: Cinco das 32 pacientes portadoras de hiperplasia congênita das suprarrenais apresentaram tecido prostático na RNM de região pélvica. Para concentração de antígeno prostático-específico de 0,1 ng/mL, obteve-se sensibilidade de 100% e especificidade de 88,9% para a detecção de tecido prostático. CONCLUSÕES: A ocorrência de tecido prostático nas pacientes portadoras de hiperplasia congênita das suprarrenais estudadas foi de 15,6%. O antígeno prostático-específico mostrou ser valioso marcador de tecido prostático nestas pacientes.OBJECTIVES: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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

A novel DAX1/NR0B1 mutation in a patient with adrenal hypoplasia congenita and hypogonadotropic hypogonadism

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):496-50

Autosomal-Recessive Mutations in MESD Cause Osteogenesis Imperfecta

Osteogenesis imperfecta (OI) comprises a genetically heterogeneous group of skeletal fragility diseases. Here, we report on five independent families with a progressively deforming type of OI, in whom we identified four homozygous truncation or frameshift mutations in MESD. Affected individuals had recurrent fractures and at least one had oligodontia. MESD encodes an endoplasmic reticulum (ER) chaperone protein for the canonical Wingless-related integration site (WNT) signaling receptors LRP5 and LRP6. Because complete absence of MESD causes embryonic lethality in mice, we hypothesized that the OI-associated mutations are hypomorphic alleles since these mutations occur downstream of the chaperone activity domain but upstream of ER-retention domain. This would be consistent with the clinical phenotypes of skeletal fragility and oligodontia in persons deficient for LRP5 and LRP6, respectively. When we expressed wild-type (WT) and mutant MESD in HEK293T cells, we detected WT MESD in cell lysate but not in conditioned medium, whereas the converse was true for mutant MESD. We observed that both WT and mutant MESD retained the ability to chaperone LRP5. Thus, 01-associated MESD mutations produce hypomorphic alleles whose failure to remain within the ER significantly reduces but does not completely eliminate LRP5 and LRP6 trafficking. Since these individuals have no eye abnormalities (which occur in individuals completely lacking LRP5) and have neither limb nor brain patterning defects (both of which occur in mice completely lacking LRP6), we infer that bone mass accrual and dental patterning are more sensitive to reduced canonical WNT signaling than are other developmental processes. Biologic agents that can increase LRP5 and LRP6-mediated WNT signaling could benefit individuals with MESD-associated OI