Human NR5A1/SF-1 mutations show decreased activity on BDNF (brain-derived neurotrophic factor), an important regulator of energy balance: testing impact of novel SF-1 mutations beyond steroidogenesis.

CONTEXT: Human NR5A1/SF-1 mutations cause 46,XY disorder of sex development (DSD) with broad phenotypic variability, and rarely cause adrenal insufficiency although SF-1 is an important transcription factor for many genes involved in steroidogenesis. In addition, the Sf-1 knockout mouse develops obesity with age. Obesity might be mediated through Sf-1 regulating activity of brain-derived neurotrophic factor (BDNF), an important regulator of energy balance in the ventromedial hypothalamus. OBJECTIVE: To characterize novel SF-1 gene variants in 4 families, clinical, genetic and functional studies were performed with respect to steroidogenesis and energy balance. PATIENTS: 5 patients with 46,XY DSD were found to harbor NR5A1/SF-1 mutations including 2 novel variations. One patient harboring a novel mutation also suffered from adrenal insufficiency. METHODS: SF-1 mutations were studied in cell systems (HEK293, JEG3) for impact on transcription of genes involved in steroidogenesis (CYP11A1, CYP17A1, HSD3B2) and in energy balance (BDNF). BDNF regulation by SF-1 was studied by promoter assays (JEG3). RESULTS: Two novel NR5A1/SF-1 mutations (Glu7Stop, His408Profs*159) were confirmed. Glu7Stop is the 4th reported SF-1 mutation causing DSD and adrenal insufficiency. In vitro studies revealed that transcription of the BDNF gene is regulated by SF-1, and that mutant SF-1 decreased BDNF promoter activation (similar to steroid enzyme promoters). However, clinical data from 16 subjects carrying SF-1 mutations showed normal birth weight and BMI. CONCLUSIONS: Glu7Stop and His408Profs*159 are novel SF-1 mutations identified in patients with 46,XY DSD and adrenal insufficiency (Glu7Stop). In vitro, SF-1 mutations affect not only steroidogenesis but also transcription of BDNF which is involved in energy balance. However, in contrast to mice, consequences on weight were not found in humans with SF-1 mutations.

Macroorchidism and panhypopituitarism: two different forms of presentation of FSH-secreting pituitary adenomas in adolescence.

BACKGROUND: FSH-secreting pituitary adenomas are extremely rare in children and are seldom associated with clinical manifestations of high serum gonadotrophin levels. Thus, most patients have a late presentation, usually as macroadenomas. CASE REPORTS: Two different clinical forms of presentation of FSH-secreting pituitary adenomas are reported: one in a 12-year-old boy with macroorchidism due to a pituitary microadenoma, probably FSH-secreting, and the other in a 15-year-old boy with panhypopituitarism due to an FSH-producing macroadenoma. Both patients presented slightly high or high FSH with low LH and high inhibin B levels. In the first case, the microadenoma was treated medically with cabergoline, which failed to reduce FSH and inhibin B levels. No radiological progression has been observed despite increasing testicular volume. In the second case, surgery was performed on the macroadenoma, leading to a decrease in FSH and inhibin B levels. The patient developed severe hypothalamic obesity and is currently under treatment with somatostatin. CONCLUSIONS: FSH-secreting pituitary tumors have an extremely variable clinical expression. The discrepancy between normal or slightly increased FSH and low LH values, together with high inhibin B levels, strongly suggests FSH hypersecretion which should be studied.

Glycogen storage disease type III with hypoketosis.

A rare case of glycogen storage disease type III with unusually absent ketone body production during hypoglycemia is presented. A 10-month-old boy presented with asymptomatic hepatomegaly. GOT/GPT 2555/1160 IU/L, CK 302 IU/L, triglycerides 1223 mg/dL, cholesterol 702 mg/dL and uric acid 7.9 mg/dL. After a 9-hour fast, glucose was 27 mg/dL and adequate lipolysis without ketogenesis was observed (total/free carnitine 34.5/20 micromol/L, free fatty acids 1620 micromol/L and beta-hydroxybutyrate 172 micromol/L). Result of MCT (medium-chain triglycerides) load test: basal hydroxybutyrate 29 micromol/L rose to 5748 micromol/L. Treatment with a fat-restricted diet supplemented with formula containing MCT was initiated and the patient presented a satisfactory initial evolution. Three months later, CK were 3000 IU/L. Muscle biopsy was diagnostic of glycogenosis. Enzymatic activity in skin fibroblasts was 0% for amylo-1,6-glucosidase. The diagnosis of glycogenosis type III was established. Echocardiography performed at that time showed non-obstructive ventricular hypertrophy. Until now hypoketosis during hypoglycemia has only been described in glycogenosis type I.

Glucose intolerance and diabetes are observed in the long-term follow-up of nonpancreatectomized patients with persistent hyperinsulinemic hypoglycemia of infancy due to mutations in the ABCC8 gene.

OBJECTIVE: To report the long-term follow-up of three nonpancreatectomized patients with persistent hyperinsulinemic hypoglycemia of infancy due to mutations in the ABCC8 gene. RESEARCH DESIGN AND METHODS: Oral glucose tolerance test (OGTT) and venous 24-h glucose-insulin profile were performed yearly from adolescence. RESULTS: Patient 1 (now aged 31 years) developed insulin-dependent diabetes at the age of 25 years. In patient 2 (now aged 17 years), impaired fasting glucose and a diabetic OGTT response with normal A1C values have been observed since the age of 10 years. In patient 3 (now aged 24 years), intolerant OGTT response and hyperglycemic episodes with normal A1C have been observed since the age of 16 years. All patients presented relatively low insulin levels during hyperglycemia, normal BMI, and negative autoantibodies (GAD antibody, insulinoma-associated protein 2, and islet cell antibody). CONCLUSIONS: Development of glucose metabolism impairment ranging from glucose intolerance to insulin-dependent diabetes is observed in the evolution of these patients.