Circulating antimüllerian hormone levels in boys decline during early puberty and correlate with inhibin B.

OBJECTIVE: To investigate peripheral levels of inhibin B and antimüllerian hormone (AMH) in boys during peripuberty and in patients with congenital hypogonadotropic hypogonadism (HH). DESIGN: Randomized, placebo-controlled trial (peripubertal boys); and cross-sectional clinical study (males with HH). SETTING: University central hospital. PATIENT(S): Twenty-eight peripubertal boys with idiopathic short stature (ISS), 19 males with Kallmann syndrome. INTERVENTION(S): Letrozole (2.5 mg/day) or placebo in boys with ISS for 2 years. MAIN OUTCOME MEASURE(S): Longitudinal follow-up observation of serum AMH and its relationship with inhibin B during early puberty and the influence of high (letrozole-treated boys) and low (males with HH) gonadotropin exposure on circulating AMH. RESULT(S): In boys with ISS receiving placebo, the decrease in AMH levels and the increase in inhibin B levels were correlated. The serum AMH level had already declined before a clinically significant increase in testis volume or serum testosterone occurred. Letrozole did not appear to modulate the decline in AMH. The AMH levels were lower in boys and young adults with Kallmann syndrome and prepubertal testes (mean: 20.9 ± 4.7 ng/mL, n = 6) as compared with prepubertal ISS boys (102.3 ± 11.9 ng/mL). CONCLUSION(S): The gonadotropin-mediated early pubertal increase in inhibin B is tightly coupled to decrease in AMH levels and may reflect androgen-mediated differentiation of Sertoli cells. Profound gonadotropin deficiency is associated with low AMH levels, suggesting impaired development of the Sertoli cell population.

Long-term effects of growth hormone therapy on patients with Prader-Willi syndrome.

AIM: To assess the effects of recombinant human growth hormone (rhGH) treatment in children with Prader-Willi syndrome. DESIGN: A 1-year study and an observational follow-up visit 10 years later. METHODS: In 20 patients with Prader-Willi syndrome (PWS): clinical assessment, laboratory tests, body composition analysis by dual energy X-ray absorptiometry, sleep polygraphy, health-related quality of life assessed by 16D. RESULTS: Only two patients had normal growth hormone secretion at baseline. All patients were significantly shorter than their expected heights, but experienced catch-up growth during growth hormone treatment. At follow-up, 13 patients had reached adult heights and were markedly taller than historical controls. The cumulative dose of rhGH over 10 years correlated inversely with the total body fat percentage (p = 0.033). However, patients remained severely obese at 10 years. Sleep polygraphy was abnormal in more than half of the patients. Health-related quality of life of the patients remained substantially below that of normal population. CONCLUSION: Growth hormone markedly improved adult height in subjects with PWS when compared to historical data. The cumulative dose of growth hormone correlated with reduction in body fat; nevertheless, patients remained severely obese.

Metabolic control and growth during exclusive growth hormone treatment in X-linked hypophosphatemic rickets.

BACKGROUND: GH may improve phosphate balance and height in X-linked hypophosphatemic rickets (XLH). This study evaluated the impact of exclusive rhGH therapy on phosphate homeostasis and growth. METHODS: Ten children (median age 12.2 years) with XLH were included in a 12-month trial with GH. Conventional treatment was discontinued 1 month prior GH (0.033 mg/kg/day); 1alpha-hydroxyvitamin D was added at 6 months and oral phosphate at 12 months, when GH was discontinued. Patients were followed 1-3 monthly until 18 months for clinical, biochemical and radiographic parameters. RESULTS: Serum phosphate Z-score increased significantly from baseline at 6 months (p = 0.005) and 9 months (p = 0.009) but returned to baseline by 12 months. Serum 1,25-dihydroxyvitamin D also increased significantly. Parathyroid function normalized. The median height Z-score was -2.2 (-2.7 to +0.4) at GH onset and -1.7 (-2.3 to +0.3) at 12 months. One patient showed a significant increase in radiographic rickets activity and 3 patients aggravation of lower limb deformity; the others showed no changes or improvement in these parameters. CONCLUSIONS: GH treatment improved serum phosphate and 1,25-dihydroxyvitamin D, normalized parathyroid function and improved longitudinal growth in XLH. It may however aggravate pre-existing skeletal deformities.

Physical exercise-induced hypoglycemia caused by failed silencing of monocarboxylate transporter 1 in pancreatic beta cells.

Exercise-induced hyperinsulinism (EIHI) is a dominantly inherited hypoglycemic disorder characterized by inappropriate insulin secretion during anaerobic exercise or on pyruvate load. We aimed to identify the molecular basis of this novel disorder of beta -cell regulation. EIHI mapped to chromosome 1 (LOD score 3.6) in a genome scan performed for two families with 10 EIHI-affected patients. Mutational analysis of the promoter of the SLC16A1 gene, which encodes monocarboxylate transporter 1 (MCT1), located under the linkage peak, revealed changes in all 13 identified patients with EIHI. Patient fibroblasts displayed abnormally high SLC16A1 transcript levels, although monocarboxylate transport activities were not changed in these cells, reflecting additional posttranscriptional control of MCT1 levels in extrapancreatic tissues. By contrast, when examined in beta cells, either of two SLC16A1 mutations identified in separate pedigrees resulted in increased protein binding to the corresponding promoter elements and marked (3- or 10-fold) transcriptional stimulation of SLC16A1 promoter-reporter constructs. These studies show that promoter-activating mutations in EIHI induce SLC16A1 expression in beta cells, where this gene is not usually transcribed, permitting pyruvate uptake and pyruvate-stimulated insulin release despite ensuing hypoglycemia. These findings describe a novel disease mechanism based on the failure of cell-specific transcriptional silencing of a gene that is highly expressed in other tissues.

Growth hormone treatment in 35 prepubertal children with achondroplasia: a five-year dose-response trial.

BACKGROUND: Achondroplasia is a skeletal dysplasia with extreme, disproportionate, short stature. AIM: In a 5-y growth hormone (GH) treatment study including 1 y without treatment, we investigated growth and body proportion response in 35 children with achondroplasia. METHODS: Patients were randomized to either 0.1 IU/kg (n = 18) or 0.2 IU/kg (n = 17) per day. GH treatment was interrupted for 12 mo after 2 y of treatment in prepubertal patients to study catch-down growth. Mean height SDS (HSDS) at start was -5.6 and -5.2 for the low- and high-dose groups, respectively, and mean age 7.3 and 6.6 y. RESULTS: Mean growth velocity (baseline 4.5/4.6 cm/y for the groups) increased significantly by 1.9/3.6 cm/y during the first year and by 0.5/1.5 cm/y during the second year. During the third year, a decrease of growth velocity was observed at 1.9/1.3 cm/y below baseline values. HSDS increased significantly by 0.6/0.8 during the first year of treatment and in total by 1.3/1.6 during the 5 y of study. Sitting height SDS improved significantly from -2.1/-1.7 to -0.8/0.2 during the study. Body proportion (sitting height/total height) or arm span did not show any significant change. CONCLUSION: GH treatment of children with achondroplasia improves height during 4 y of therapy without adverse effect on trunk-leg disproportion. The short-term effect is comparable to that reported in Turner and Noonan syndrome and in idiopathic short stature.

Gluten-free diet may alleviate depressive and behavioural symptoms in adolescents with coeliac disease: a prospective follow-up case-series study.

BACKGROUND: Coeliac disease in adolescents has been associated with an increased prevalence of depressive and disruptive behavioural disorders, particularly in the phase before diet treatment. We studied the possible effects of a gluten-free diet on psychiatric symptoms, on hormonal status (prolactin, thyroidal function) and on large neutral amino acid serum concentrations in adolescents with coeliac disease commencing a gluten-free diet. METHODS: Nine adolescents with celiac disease, aged 12 to 16 years, were assessed using the semi-structured K-SADS-Present and Lifetime Diagnostic interview and several symptom scales. Seven of them were followed at 1 to 2, 3, and 6 months on a gluten-free diet. RESULTS: Adolescent coeliac disease patients with depression had significantly lower pre-diet tryptophan/ competing amino-acid (CAA) ratios and free tryptophan concentrations, and significantly higher biopsy morning prolactin levels compared to those without depression. A significant decrease in psychiatric symptoms was found at 3 months on a gluten-free diet compared to patients' baseline condition, coinciding with significantly decreased coeliac disease activity and prolactin levels and with a significant increase in serum concentrations of CAAs. CONCLUSION: Although our results of the amino acid analysis and prolactin levels in adolescents are only preliminary, they give support to previous findings on patients with coeliac disease, suggesting that serotonergic dysfunction due to impaired availability of tryptophan may play a role in vulnerability to depressive and behavioural disorders also among adolescents with untreated coeliac disease.

Growth hormone treatment in Aarskog syndrome: analysis of the KIGS (Pharmacia International Growth Database) data.

Aarskog syndrome is an X-linked disorder characterized by faciogenital dysplasia and short stature. The present study set out to determine the effect of growth hormone (GH) therapy in patients with Aarskog syndrome enrolled in KIGS--the Pharmacia International Growth Database. Twenty-one patients (20 males) were evaluated. Median age at start of treatment was 8.3 years (10-90th percentiles, 5.1-14.1 years) and median height SDS was -2.8 (10-90th percentiles, -2.1 to -3.7). The median dose of GH was 0.22 mg/kg/week (10-90th percentiles, 0.15-0.30 mg/kg/week) given at a median frequency of six (4-7) times per week. Prepubertal patients were followed longitudinally for 1 year (n = 13) or 3 years (n = 7). After 1 year, the median height SDS had improved from -2.8 to -2.3 in 13 patients. After 3 years, height SDS had improved significantly (p <0.05) to -1.8 (10-90th percentiles, -2.1 to -1.1) in the seven patients. No adverse events were noted. Although final height data for these patients are still awaited, the present results support the use of GH to promote growth in children with Aarskog syndrome.

Physical exercise-induced hyperinsulinemic hypoglycemia is an autosomal-dominant trait characterized by abnormal pyruvate-induced insulin release.

We have identified patients in whom strenuous physical exercise leads to hypoglycemia caused by inappropriate insulin release (exercise-induced hyperinsulinism [EIHI]). The aim of the present study was to test the hypothesis that the increased levels of lactate and/or pyruvate during anaerobic exercise would trigger the aberrant insulin secretion in these patients. A total of 12 patients (8 women and 4 men from two families) were diagnosed with EIHI, based on hypoglycemia and a more than threefold increase in plasma insulin induced by a 10-min bicycle exercise test. The mode of inheritance was autosomal dominant in these families. The acute response of insulin release to a bolus of intravenous pyruvate (13.9 mmol/1.73 m(2)) was studied in the patients and eight healthy control subjects. Insulin secretion did not respond to the pyruvate bolus in healthy control subjects. However, all EIHI patients responded to pyruvate, displaying a brisk increase in plasma insulin. The 1 + 3-min peak response was 5.6-fold in the patients and 0.9-fold in the control subjects (P < 0.001). To test the hypothesis that the pathogenesis of EIHI would involve monocarboxylate transport or metabolism in the beta-cell, we sequenced the genes encoding the known monocarboxylate transporter proteins and tested the transport of pyruvate into patient fibroblasts. The results revealed normal coding sequences and pyruvate transport. In conclusion, EIHI represents a new autosomal-dominant hyperinsulinemia syndrome that may be more common than has been realized. The pyruvate test provides a simple, safe, and specific diagnostic test for this condition.

Growth after renal transplantation in infancy or early childhood.

Forty-one children <5 years of age at kidney transplantation (TX) were investigated for growth, bone age, and renal function up to 7 years ( n=26) after TX. All children received triple immunosuppression, including alternate-day corticosteroid treatment. Catch-up growth was seen in 81% of 30 children without growth hormone (GH) treatment. Children <2 years of age without GH had a mean height standard deviation score (hSDS) of -1.1+/-0.8 at TX and -1.1+/-0.5 at 7 years; children between 2 and 5 years improved their hSDS from -1.9+/-0.9 to -0.4+/-0.8 ( P<0.0001). The hSDS at TX correlated inversely with the DeltahSDS from TX to 7 years ( r=-0.80, P=0.0002). Glomerular filtrations rate (GFR) at 5 years post TX correlated with the subsequent growth rate from 5 to 7 years TX ( r=0.58, P=0.01). Catch-up growth was seen in all 11 children receiving GH. Their mean hSDS improved from -2.5+/-0.9 to -1.1+/-0.9 ( P<0.0001). In the majority of children receiving a kidney graft in early life, triple immunosuppression with alternate-day steroids can ensure catch-up growth. In children <5 years of age at TX, growth is predicted better by the degree of stunting than by age.