Mitchell-Riley Syndrome: Improving Clinical Outcomes and Searching for Functional Impact of RFX-6 Mutations

AIMS/HYPOTHESIS

Caused by biallelic mutations of the gene encoding the transcription factor RFX6, the rare Mitchell-Riley syndrome (MRS) comprises neonatal diabetes, pancreatic hypoplasia, gallbladder agenesis or hypoplasia, duodenal atresia, and severe chronic diarrhea. So far, sixteen cases have been reported, all with a poor prognosis. This study discusses the multidisciplinary intensive clinical management of 4 new cases of MRS that survived over the first 2 years of life. Moreover, it demonstrates how the mutations impair the RFX6 function.

METHODS

Clinical records were analyzed and described in detail. The functional impact of two RFX6^R181W and RFX6^V506G variants was assessed by measuring their ability to transactivate insulin transcription and genes that encode the L-type calcium channels required for normal pancreatic beta-cell function.

RESULTS

All four patients were small for gestational age (SGA) and prenatally diagnosed with duodenal atresia. They presented with neonatal diabetes early in life and were treated with intravenous insulin therapy before switching to subcutaneous insulin pump therapy. All patients faced recurrent hypoglycemic episodes, exacerbated when parenteral nutrition (PN) was disconnected. A sensor-augmented insulin pump therapy with a predictive low-glucose suspension system was installed with good results. One patient had a homozygous c.1517T>G (p.Val506Gly) mutation, two patients had a homozygous p.Arg181Trp mutation, and one patient presented with new compound heterozygosity. The RFX6^V506G and RFX6^R181W mutations failed to transactivate the expression of insulin and genes that encode L-type calcium channel subunits required for normal pancreatic beta-cell function.

CONCLUSIONS/INTERPRETATION

Multidisciplinary and intensive disease management improved the clinical outcomes in four patients with MRS, including adjustment of parenteral/oral nutrition progression and advanced diabetes technologies. A better understanding of RFX6 function, in both intestine and pancreas cells, may break ground in new therapies, particularly regarding the use of drugs that modulate the enteroendocrine system.

Position statement on the diagnosis and management of premature/primary ovarian insufficiency (except Turner Syndrome)

Premature ovarian insufficiency (POI) is a rare pathology affecting 1-2% of under-40 year-old women, 1 in 1000 under-30 year-olds and 1 in 10,000 under-20 year-olds. There are multiple etiologies, which can be classified as primary (chromosomal, genetic, auto-immune) and secondary or iatrogenic (surgical, or secondary to chemotherapy and/or radiotherapy). Despite important progress in genetics, more than 60% of cases of primary POI still have no identifiable etiology; these cases are known as idiopathic POI. POI is defined by the association of 1 clinical and 1 biological criterion: primary or secondary amenorrhea or spaniomenorrhea of>4 months with onset before 40 year of age, and elevated follicle-stimulating hormone (FSH)>25IU/L on 2 assays at>4 weeks' interval. Estradiol level is low, and anti-Müllerian hormone (AMH) levels have usually collapsed. Initial etiological work-up comprises auto-immune assessment, karyotype, FMR1 premutation screening and gene-panel study. If all of these are normal, the patient and parents may be offered genome-wide analysis under the "France Génomique" project. The term ovarian insufficiency suggests that the dysfunction is not necessarily definitive. In some cases, ovarian function may fluctuate, and spontaneous pregnancy is possible in around 6% of cases. In confirmed POI, hormone replacement therapy is to be recommended at least up to the physiological menopause age of 51 years. Management in a rare diseases center may be proposed.

Impact of deprivation on hospital efficiency and financial balance in paediatrics

Background

In healthcare systems where hospital tariffs are based on average national length of stay (LOS), deprived patients may be a source of inefficiency for hospitals as deprivation has been shown to be associated with increased LOS. They may also negatively impact hospitals’ financial balance as few hospital payment methods include deprivation. Our objective was to study the impact of deprivation on hospital efficiency and financial balance.

Methods

A study was carried out using an exhaustive national hospital discharge database. All inpatient stays in mainland France between 2012 and 2014 by children over 28 days and under 18 in hospitals with a paediatric ward were included. Deprivation was estimated with an ecological deprivation index divided into national quintiles. Efficiency was assessed by variations in patients’ LOS compared to different mean national LOS (paediatric LOS, LOS of admissions for a similar condition...). Financial balance was assessed at the admission level through the ratio of production costs and revenues and at the hospital level with the difference between all revenues and production costs for said hospital. Multivariate models assessed the association between those indicators and deprivation.

Results

4,124,510 inpatient stays were included. LOS was shorter than national means for less deprived patients and longer for the more deprived, and the difference was higher for diagnosis-related groups (DRGs) that included both adult and paediatric patients compared to paediatric-only DRGs. The multivariate model confirmed those significant associations. Deprivation also had a significant impact on hospitals’ financial balance, especially for hospitals with a percentage of paediatric patients in the two most deprived quintiles between 20% and 60%.

Conclusions

Measures to reform hospital payment methods must be encouraged to improve resource allocation efficiency and equity in access to good paediatric care.

Key messages

A reform of hospital funding to better account for deprivation is needed. A modulation of tariffs using an allocation key at the patient level must be considered to mitigate the effect of deprivation. DRGs specific to children should be encouraged to become the norm rather the exception to provide an adequate picture of resources used during admission and therefore an appropriate tariff.

Hyponatremia in children under 100 days old: incidence and etiologies

Hyponatremia is one of the most common electrolyte disorders in hospitalized children. The underlying mechanisms are poorly understood and potentially multifactorial, making management difficult, particularly in neonates. This retrospective study aimed to determine the incidence and etiologies of hyponatremia in hospitalized children under the age of 100 days, in our pediatric tertiary care hospital over a 1-year period. The etiology of hyponatremia was determined by reviewing the data noted in each patient's medical reports. Neonatal hyponatremia had a prevalence of 4.3% (86/2012 patients) and was mostly hospital-acquired (74/86 patients). Fifty-nine patients (68.9%) were preterm neonates. The etiology was iatrogenic in 26 cases (30.2%). In other cases, hyponatremia was due to transient (23 patients, 26.7%) or genetic abnormalities of the renal mineralocorticoid pathway (3 patients, 3.4%), SIADH (12 patients, 14%), digestive disease (3 patients, 3.5%), acute renal failure (3 patients, 3.5%), or heart failure (1 patient, 1.2%).Conclusion: Our findings confirm that hyponatremia is a frequent electrolyte disorder in neonates. Various mechanisms underlie this condition, most of which could be prevented by optimized management. The prevalence of genetic hypoaldosteronism and pseudohypoaldosteronism was higher than expected. We provide a simple diagram to help physicians identify the mechanisms underlying neonatal hyponatremia. What is Known: • In neonates, hyponatremia may be multifactorial, making it difficult to treat. • Newborns display partial resistance to aldosterone, and preterms have a defect in aldosterone secretion. What is New: • Four percent of hospitalized neonates had hyponatremia, 86% hospital-acquired. Hyponatremia was due to a transient or constitutional defect of the mineralocorticoid pathway in 26/86 patients (30%) which is higher than expected. • We propose a tree diagram for improving the management of hyponatremia in neonates.

High prevalence of syndromic disorders in patients with non-isolated central precocious puberty

Objective Non-idiopathic CPP is caused by acquired or congenital hypothalamic lesions visible on MRI or is associated with various complex genetic and/or syndromic disorders. This study investigated the different types and prevalence of non-isolated CPP phenotypes. Design and Methods This observational cohort study included all patients identified as having non-idiopathic CPP in the database of a single academic pediatric care center over a period of 11.5 years. Patients were classified on the basis of MRI findings for the CNS as having either hypothalamic lesions or complex syndromic phenotypes without structural lesions of the hypothalamus. Results In total, 63 consecutive children (42 girls and 21 boys) with non-isolated CPP were identified. Diverse diseases were detected, and the hypothalamic lesions visible on MRI (n = 28, 45% of cases) included hamartomas (n = 17; either isolated or with an associated syndromic phenotype), optic gliomas (n = 8; with or without neurofibromatosis type 1), malformations (n = 3) with interhypothalamic adhesions (n = 2; isolated or associated with syndromic CNS midline abnormalities, such as optic nerve hypoplasia, ectopic posterior pituitary) or arachnoid cysts (n = 1). The patients with non-structural hypothalamic lesions (n = 35, 55% of cases) had narcolepsy (n = 9), RASopathies (n = 4), encephalopathy or autism spectrum disorders with or without chromosomal abnormalities (n = 15) and other complex syndromic disorders (n = 7). Conclusion Our findings suggest that a large proportion (55%) of patients with non-isolated probable non-idiopathic CPP may have complex disorders without structural hypothalamic lesions on MRI. Future studies should explore the pathophysiological relevance of the mechanisms underlying CPP in these disorders.

Diagnosis and management of hyperthyroidism from prenatal life to adolescence

Hyperthyroidism in children is a rare heterogeneous syndrome characterized by excessive thyroid hormone production. Its manifestations differ according to disease severity. For all forms of hyperthyroidism, treatment aims to restore a euthyroid state, enabling the child to demonstrate appropriate metabolism, growth, and neurocognitive development. Graves' disease is the most frequent cause of hyperthyroidism in children. Treatment modalities include antithyroid drugs, with the advantage that prolonged treatment for several years can be followed by freedom from medical intervention in about 40-50% of cases. It may also be treated with radioactive iodine or, less frequently, thyroidectomy, these more radical treatments both necessitating subsequent lifelong levothyroxine treatment. Particular care is required in the management of pregnant women with Graves' disease. Fetal and neonatal forms of hyperthyroidism are transient and rare, but nevertheless serious. Here, we provide an overview of the best approach to hyperthyroidism diagnosis and management, from fetal development to adolescence.

Association of maternal nutrition with transient neonatal hyperinsulinism

Objective

The objective was to determine whether maternal nutritional factors are associated with transient neonatal hyperinsulinism (HI).

Design and setting

Case control study in 4 French tertiary Obstetrics and Neonatology Departments between 2008 and 2015.

Methods

Sixty-seven mothers of neonates diagnosed with transient hyperinsulinism and 113 mothers of controls were included. The screening for hyperinsulinemic hypoglycemia in neonates was performed because of clinical symptoms suggestive of hypoglycemia or in the presence of conventional risk factors (small-for-gestational-age, prematurity, anoxo-ischemia, hypothermia, macrosomia, gestational diabetes). Hyperinsulinemic hypoglycemia was confirmed in the HI neonates and ruled out in the controls. This allowed for comparing maternal nutrition in cases and controls in a context of similar risk factors. One to 2 mothers of control neonates were included per case, and a food frequency questionnaire was addressed to the mothers between day 5 and day 10 after the birth of their newborn.

Results

Crude odds ratio showed that maternal weight gain, abnormal fetal rate, C-section, gender, consumption of fresh cooked vegetables, fresh fruits and fruit juices, low fat diary products, light fat products, and daily bread were significantly associated with hyperinsulinism. Maternal body mass index, hypertension, gestational diabetes, birth weight percentile, gestational age and 5-minute Apgar score were not related to HI. In a multiple backward logistic regression model, consumption of fresh cooked vegetable ≥1/day (OR = 0.33 [0.14–0.77]) and light-fat products ≥1/week (OR = 0.24 [0.08–0.71]) was protective against hyperinsulinism, whereas gestational weight gain >20 kg (OR = 9.5 [2.0–45.5]) and between 15–20 kg (OR = 4.0 [1.2–14.0]), abnormal fetal heart rate (OR = 4.4 [1.6–12.0]), and C-section (OR = 3.4 [1.3–8.9]) were risk factors.

Conclusions

A diet rich in fresh cooked vegetable and reduced in fat, together with the avoidance of a high gestational weight gain may be protective against transient neonatal hyperinsulinism.

Graves' disease in children

Graves' disease is an autoimmune disorder resulting from thyrotropin receptor stimulation by autoantibodies. It may occur at any age during childhood, but its frequency increases with age, peaking during adolescence. Symptoms and signs are often recognizable and proportional to the increase in serum free thyroid hormone levels. Antithyroid drug treatment with methimazole (or carbimazole) is recommended for initial treatment, but relapse rates are high, with remission achieved in only 30% of children after a first course of treatment for about two years. More prolonged medical treatment may increase the remission rate to up to 50%. Alternative treatments, such as radioactive iodine or thyroidectomy, are considered in cases of relapse, lack of compliance or antithyroid drug toxicity. Relapse risk decreases with increasing duration of the first course of antithyroid drug treatment. The identification of other predictive factors, such as severe biochemical hyperthyroidism at diagnosis, young age and the absence of other autoimmune conditions, has made it possible to stratify patients according to the risk of relapse, leading to improvements in patient management, by facilitating the identification of patients requiring long-term antithyroid drug treatment or early alternative therapy.

Dental caries and enamelin haplotype

In the literature, the enamelin gene ENAM has been repeatedly designated as a possible candidate for caries susceptibility. Here, we checked whether ENAM variants could increase caries susceptibility. To this aim, we sequenced coding exons and exon-intron boundaries of ENAM in 250 children with a severe caries phenotype and in 149 caries-free patients from 9 French hospital groups. In total, 23 single-nucleotide polymorphisms (SNPs) were found, but none appeared to be responsible for a direct change of ENAM function. Six SNPs had a high minor allele frequency (MAF) and 6 others were identified for the first time. Statistical and evolutionary analyses showed that none of these SNPs was associated with caries susceptibility or caries protection when studied separately and challenged with environmental factors. However, haplotype interaction analysis showed that the presence, in a same variant, of 2 exonic SNPs (rs7671281 and rs3796704; MAF 0.12 and 0.10, respectively), both changing an amino acid in the protein region encoded by exon 10 (p.I648T and p.R763Q, respectively), increased caries susceptibility 2.66-fold independent of the environmental risk factors. These findings support ENAM as a gene candidate for caries susceptibility in the studied population.

BPIFB1 is a lung-specific autoantigen associated with interstitial lung disease

Interstitial lung disease (ILD) is a complex and heterogeneous disorder that is often associated with autoimmune syndromes. Despite the connection between ILD and autoimmunity, it remains unclear whether ILD can develop from an autoimmune response that specifically targets the lung parenchyma. We examined a severe form of autoimmune disease, autoimmune polyglandular syndrome type 1 (APS1), and established a strong link between an autoimmune response to the lung-specific protein BPIFB1 (bactericidal/permeability-increasing fold-containing B1) and clinical ILD. Screening of a large cohort of APS1 patients revealed autoantibodies to BPIFB1 in 9.6% of APS1 subjects overall and in 100% of APS1 subjects with ILD. Further investigation of ILD outside the APS1 disorder revealed BPIFB1 autoantibodies present in 14.6% of patients with connective tissue disease-associated ILD and in 12.0% of patients with idiopathic ILD. The animal model for APS1, Aire⁻/⁻ mice, harbors autoantibodies to a similar lung antigen (BPIFB9); these autoantibodies are a marker for ILD. We found that a defect in thymic tolerance was responsible for the production of BPIFB9 autoantibodies and the development of ILD. We also found that immunoreactivity targeting BPIFB1 independent of a defect in Aire also led to ILD, consistent with our discovery of BPIFB1 autoantibodies in non-APS1 patients. Overall, our results demonstrate that autoimmunity targeting the lung-specific antigen BPIFB1 may contribute to the pathogenesis of ILD in patients with APS1 and in subsets of patients with non-APS1 ILD, demonstrating the role of lung-specific autoimmunity in the genesis of ILD.

A simple and fast non-radioactive bridging immunoassay for insulin autoantibodies

Type 1 diabetes (T1D) is an autoimmune disease which results from the destruction of pancreatic beta cells. Autoantibodies directed against islet antigens are valuable diagnostic tools. Insulin autoantibodies (IAAs) are usually the first to appear and also the most difficult to detect amongst the four major islet autoantibodies. A non-radioactive IAA bridging ELISA was developed to this end. In this assay, one site of the IAAs from serum samples is bound to a hapten-labeled insulin (GC300-insulin), which is subsequently captured on anti-GC300 antibody-coated 96-well plates. The other site of the IAAs is bound to biotinylated insulin, allowing the complex to be detected by an enzyme-streptavidin conjugate. In the present study, 50 serum samples from patients with newly diagnosed T1D and 100 control sera from non-diabetic individuals were analyzed with our new assay and the results were correlated with an IAA radioimmunoassay (RIA). Using IAA bridging ELISA, IAAs were detected in 32 out of 50 T1D children, whereas with IAA RIA, 41 out of 50 children with newly diagnosed T1D were scored as positive. In conclusion, the IAA bridging ELISA could serve as an attractive approach for rapid and automated detection of IAAs in T1D patients for diagnostic purposes.

Common SNPs of AmelogeninX (AMELX) and dental caries susceptibility

Genetic approaches have shown that several genes could modify caries susceptibility; AmelogeninX (AMELX) has been repeatedly designated. Here, we hypothesized that AMELX mutations resulting in discrete changes of enamel microstructure may be found in children with a severe caries phenotype. In parallel, possible AMELX mutations that could explain resistance to caries may be found in caries-free patients. In this study, coding exons of AMELX and exon-intron boundaries were sequenced in 399 individuals with extensive caries (250) or caries-free (149) individuals from nine French hospital groups. No mutation responsible for a direct change of amelogenin function was identified. Seven single-nucleotide polymorphisms (SNPs) were found, 3 presenting a high allele frequency, and 1 being detected for the first time. Three SNPs were located in coding regions, 2 of them being non-synonymous. Both evolutionary and statistical analyses showed that none of these SNPs was associated with caries susceptibility, suggesting that AMELX is not a gene candidate in our studied population.

Hyperthyroidism in childhood: causes, when and how to treat

Graves' disease (GD) is the most common cause of hyperthyroidism in children. This review gives an overview and update of management of GD. Antithyroid drugs (ATD) are recommended as the initial treatment, but the major problem is the high relapse rate (30%) as remission is achieved after a first course of ATD. More prolonged medical treatment may increase the remission rate up to 50%. Alternative treatments, such as radioactive iodine or thyroidectomy, are considered in cases of relapse, lack of compliance, or ATD toxicity. Therefore, clinicians have sought prognostic indicators of remission. Relapse risk decreases with longer duration of the first course of ATD treatment, highlighting the positive impact of a long period of primary ATD treatment on outcome. The identification of other predictive factors such as severe biochemical hyperthyroidism at diagnosis, young age, and absence of other autoimmune conditions has made it possible to stratify patients according to the risk of relapse after ATD treatment, leading to improvement in patient management by facilitating the identification of patients requiring long-term ATD or early alternative therapy. Neonatal autoimmune hyperthyroidism is generally transient, occurring in only about 2% of the offspring of mothers with GD. Cardiac insufficiency, intrauterine growth retardation, craniostenosis, microcephaly and psychomotor disabilities are the major risks in these infants and highlight the importance of thyroid hormone receptor antibody determination throughout pregnancy in women with GD, as well as highlighting the need for early diagnosis and treatment of hyperthyroidism.

Phenotypic homogeneity and genotypic variability in a large series of congenital isolated ACTH-deficiency patients with TPIT gene mutations

CONTEXT

Congenital isolated ACTH deficiency (IAD) is a rare disease characterized by low plasma ACTH and cortisol levels and preservation of all other pituitary hormones. This condition was poorly defined before we identified TPIT, a T-box transcription factor with a specific role in differentiation of the corticotroph lineage in mice and humans, as its principal molecular cause.

OBJECTIVE

We have enlarged our series of IAD patients to better characterize the phenotype and the genotype of this rare disease.

DESIGN

Each exon of the TPIT gene was amplified and sequenced in IAD patients without any identified cause. A functional analysis of each new TPIT mutation was performed.

RESULTS

We described the largest series of 91 IAD patients and identified three distinct groups: neonatal onset complete or partial IAD or late onset IAD. We did not identify any TPIT mutation in patients with partial or late-onset IAD. However, we found a TPIT mutation in 65% of patients with neonatal-onset complete IAD. These patients are homozygous or compound heterozygous for TPIT mutations, and their parents are healthy heterozygous carriers. We identified nine new mutations: four missense, one one-nucleotide deletion, three splice-site mutations, and one large deletion. TPIT mutations lead to loss of function by different mechanisms, such as non-sense-mediated mRNA decay, abnormal mRNA splicing, loss of TPIT DNA binding or protein-protein interaction defects.

CONCLUSION

TPIT mutations are responsible for two thirds of neonatal-onset complete IAD but can not be detected in partial or late-onset IAD.

Pituitary-thyroid feedback in a patient with a sporadic activating thyrotropin (TSH) receptor mutation: implication that thyroid-secreted factors other than thyroid hormones contribute to serum TSH levels

CONTEXT

Constitutive mutations of the TSH receptor gene are a rare cause of severe congenital hyperthyroidism. Persistent TSH suppression has been described in euthyroid Graves' disease patients treated with antithyroid drugs. An ultrashort negative feedback loop affecting TSH secretion by activating the pituitary TSH receptor with TSH receptor autoantibodies has been suggested as a possible mechanism of TSH suppression in these patients.

OBJECTIVE AND DESIGN

The aim of the study was to determine whether TSH suppression also occurs in euthyroid treated patients with non-autoimmune hyperthyroidism. We investigated the outcome of pituitary-thyroid feedback in a patient carrying an activating mutation of the TSH-R gene in an observational prospective study. Repeated clinical investigations from birth until the age of 14 yr are presented for the patient on drug treatment and after radical treatment.

RESULTS

TSH was consistently undetectable or present at very low concentrations in the serum for several years, although FT(4) and FT(3) concentrations remained mostly in the normal range. Moreover, serum TSH concentrations increased only slightly when serum FT(4) concentrations fell below normal levels. During drug treatment, serum TSH concentrations expressed as a function of serum FT(4) and FT(3) concentrations were significantly lower than those for control or congenital hypothyroid populations. By contrast, after radical treatment, serum TSH levels increased, reaching the normal range, and low serum FT(4) and FT(3) concentrations were associated with appropriate increases in serum TSH concentrations.

CONCLUSION

These data provide insight into the regulation of serum TSH concentrations and suggest an alternative mechanism, in addition to serum thyroid hormone levels, for adjusting TSH secretion.

Medullary thyroid carcinoma identified within the first year of life in children with hereditary multiple endocrine neoplasia type 2A (codon 634) and 2B

CONTEXT

Early prophylactic thyroidectomy in patients with multiple endocrine neoplasia (MEN) type 2 offers the best chance for a normal life expectancy.

OBJECTIVE

To analyze the results of thyroidectomy performed during the first year of life in six patients with MEN 2A (codon 634) or MEN 2B (codon 918) syndrome.

DESIGN AND SETTING

A university hospital-based prospective study from 2001 to 2008.

SUBJECTS AND METHODS

Six family members affected either by MEN 2A (n=3) or MEN 2B (n=3) syndrome were identified through neonatal genetic screening.

RESULTS

Total thyroidectomy was performed at a median age of 0.8 year in the six patients, with central lymph node dissection in five. Bilateral millimetric medullary thyroid carcinoma (MTC) was found in all patients, with a unilateral lymph node micrometastasis in two of the three MEN 2B patients. Before thyroidectomy, MEN 2B patients had much higher basal serum calcitonin levels than those with MEN 2A and controls. After thyroidectomy, with a median follow-up of 3.3 years, the six patients had no evidence of persistent MTC.

CONCLUSION

Bilateral millimetric MTC may be present during the first year of life in these patients, with lymph node metastases also occurring in MEN 2B patients. These results support a total thyroidectomy at the age of about one year in MEN 2A (codon 634) children with an abnormal serum calcitonin level, and a total thyroidectomy with central neck dissection within the first weeks of life in MEN 2B patients.

Kallmann's syndrome: a comparison of the reproductive phenotypes in men carrying KAL1 and FGFR1/KAL2 mutations

CONTEXT

Kallmann's syndrome (KS) is a genetically heterogeneous disorder consisting of congenital hypogonadotropic hypogonadism (CHH) with anosmia or hyposmia.

OBJECTIVE

Our objective was to compare the reproductive phenotypes of men harboring KAL1 and FGFR1/KAL2 mutations.

DESIGN AND PATIENTS

We studied the endocrine features reflecting gonadotropic-testicular axis function in 39 men; 21 had mutations in KAL1 and 18 in FGFR1/KAL2, but none had additional mutations in PROK-2 or PROKR-2 genes.

RESULTS

Puberty failed to occur in the patients with KAL1 mutations, all of whom had complete CHH. Three patients with FGFR1/KAL2 mutations had normal puberty, were eugonadal, and had normal testosterone and gonadotropin levels. Cryptorchidism was more frequent (14 of 21 vs. 3 of 15; P<00.1) and testicular volume (2.4+/-1.1 vs. 5.4+/-2.4 ml; P<0.001) was smaller in CHH subjects with KAL1 mutations than in subjects with FGFR1/KAL2 mutations. The mean basal plasma FSH level (0.72+/-0.47 vs. 1.48+/-0.62 IU/liter; P<0.05), serum inhibin B level (19.3+/-10.6 vs. 39.5+/-19.3 pg/ml; P<0.005), basal LH plasma level (0.57+/-0.54 vs. 1.0+/-0.6 IU/liter; P<0.01), and GnRH-stimulated LH plasma level (1.2+/-1.0 vs. 4.1+/-3.5 IU/liter; P<0.01) were significantly lower in the subjects with KAL1 mutations. LH pulsatility was studied in 13 CHH subjects with KAL1 mutations and seven subjects with FGFR1/KAL2 mutations; LH secretion was nonpulsatile in all the subjects, but mean LH levels were lower in those with KAL1 mutations.

CONCLUSION

KAL1 mutations result in a more severe reproductive phenotype than FGFR1/KAL2 mutations. The latter are associated with a broader spectrum of pubertal development and with less severe impairment of gonadotropin secretion.

Management of short stature with GnRH agonist and co-treatment with growth hormone: a controversial issue

Adolescent growth is the focus of several interventions aimed at increasing the amplitude of the adolescent spurt. Favorable results with GnRH agonists in precocious puberty have encouraged attempts to increase the duration of the adolescent growth spurt by delaying normal puberty in short individuals using GnRH agonists with or without growth hormone. These approaches remain highly controversial, have not been validated and approved for use by regulatory authorities and were the topic of a session at the 6th International Conference on the Onset of Puberty. Here we review the available information on the efficacy and safety of this approach. GnRH agonists, when used outside the context of precocious puberty, induce a modest gain when used for extended periods of time. Several trials have now shown that growth hormone alone can modestly increase adult height in short adolescents with idiopathic short stature or in those born small for gestational age. The association of growth hormone and GnRH agonists still lacks a definite demonstration of its additional efficacy and available results do not allow firm conclusions. In conclusion, watchful waiting or sex steroids in delayed puberty are generally the best options in short children presenting around puberty. However, long-term and adequately powered clinical trials, focusing on efficacy, safety and clinical significance are needed to fully evaluate the combination of growth hormone and GnRH agonists in short adolescents. In the meanwhile, these approaches should be considered as experimental.

Role of beta-cells in type 1 diabetes pathogenesis

Whether autoimmunity results primarily from a defect of the immune system, target organ dysfunction, or both remains an open issue in most human autoimmune diseases. The highly multigenic background on which diabetes develops in the NOD mouse and in the human suggests that numerous gene variants associate in contributing to activation of autoimmunity to beta-cells. Both immune genes and islet-related genes are involved. The presence of beta-cells is required for initiation of diabetes autoimmunity to proceed. Available experiments in the NOD mouse and epidemiological evidence in the human point to proinsulin as a key autoantigen in diabetes. The functional importance of insulin, the high number of autoantigens characterized at different stages of diabetes, and their clustering within beta-cell subparticles point to the islet as a starting point in the initiation phase of the disease. Genes that direct the autoimmune reaction toward the beta-cell target, autoantigens that are recognized by autoreactive B- and T-cells along the autoimmune process, the importance of beta-cells in the activation of autoreactive lymphocytes, and the expression level of key beta-cell molecules along diabetes development are successively considered in this review.

Breast inflammatory gigantomastia in a context of immune-mediated diseases

CONTEXT

Localized breast lesions have been described in lupic or diabetic patients. However, the description of breast gigantomastia in women presenting with autoimmune diseases has not been reported.

SETTING

The study took place within the Department of Endocrinology and Reproductive Medicine, Necker Hospital, Paris, France.

PATIENTS

We describe eight patients with inflammatory gigantomastia, occurring in a context of immune-mediated diseases: myasthenia, chronic arthritis, or thyroiditis.

MAIN OUTCOME MEASURES

Together with hormonal, immunological, and breast magnetic resonance imaging (MRI) evaluation, breast histology enabled us to perform immunocytochemical and indirect immunofluorescence studies. Control sera were obtained from patients with (n = 10) and without (n = 7) antinuclear antibodies.

RESULTS

Six of the eight patients developed gigantomastia either at puberty or during pregnancy. Neither a hormonal oversecretion nor a specific immunological pattern was observed. All patients except one presented antinuclear antibodies. Histological study revealed a diffuse, stromal hyperplasia and a severe atrophy of the lobules. A rarefaction of adipocytes was also noted, as previously suggested on MRI. There was a perilobular lymphocytic infiltrate made of CD3+ lymphocytes. Study of sera from five of six cases of gigantomastia showed a nuclear immunofluorescence pattern in normal mammary ductal and lobular glandular epithelium, as well as in kidney and intestine epithelial cells. In control sera, a nuclear signal was observed only when antinuclear antibodies were present.

CONCLUSIONS

We suggest that breast tissue may be a target tissue in autoimmune diseases, this process being favored by the hormonal milieu. However, the precise mechanism of such association is not individualized. The fact that stromal hyperplasia is the main histological feature justifies the search for the involvement of growth factors in such a process.

Adult height after ketoconazole treatment in patients with familial male-limited precocious puberty

Familial male-limited precocious puberty is a rare cause of precocious puberty due to activating mutations of the LH receptor, leading to early onset virilization and short stature. Two therapeutic approaches have been proposed: the P450 cytochrome inhibitor ketoconazole or combined treatment with spironolactone and testolactone. Results on adult heights have not been reported to date after these two treatments, and in this study we present results from five patients treated with ketoconazole at a median dose of 16.2 mg/kg.d for a median of 6.2 yr. Adult height was 173 cm (median; interquartile range, 14), similar to target height (175 cm; interquartile range, 9) and significantly higher than pretreatment predicted height (165 cm; interquartile range, 12; P < 0.01). During treatment, 39 of 58 (68%) testosterone measurements were less than 0.5 ng/ml (1.7 nmol/liter), nine of 58 (15%) were between 0.5 and 1 ng/ml (3.5 nmol/liter), and 10 of 58 (17%) were above 1 ng/ml. We observed a physiological increase in GnRH-stimulated LH levels after the age of 10 yr, and none of the patients had early activation of the gonadotropic axis. Liver tolerance was excellent, and only one patient had a transient and modest increase in serum transaminases. We conclude that ketoconazole is an efficient and well tolerated long-term treatment of familial male-limited precocious puberty that should be proposed as a first line therapy.

Can we increase adolescent growth?

Adolescent growth represents 15-20% of adult height and has been the focus of several treatment interventions, aiming at increasing the amplitude of the adolescent spurt. Importantly, pre- and early puberty are times when patients and families seek medical help and when estimates of adult height are more accurate than in younger children. We review the current approaches aimed at increasing pubertal growth in short children and knowledge about their results and risks. GnRH agonists, when used outside the context of precocious puberty, induce a modest gain (4 cm) when they are used for more than 3 years. Their effects on bone mass, body composition and possibly on psychosocial parameters limit their use. Several trials have now shown that GH can increase adult height of short adolescents with idiopathic short stature or born small for gestational age. However, the amplitude of the effect is modest and of dubious clinical significance. Lastly, the association of both approaches is rather popular among pediatric endocrinologists but still lacks a definite demonstration of its efficacy. In conclusion, we have gained insight in the median effects of some of these treatments and overoptimistic initial expectations are now refocused. However, we still have a long way to go before we truly evaluate the factors affecting the variable individual responses to these treatments, their clinical significance and their cost-benefit balance.

Destruction of conditional insulinoma cell lines in NOD mice: a role for autoimmunity

AIMS/HYPOTHESIS

betaTC-tet (H2(k)) is a conditional insulinoma cell line derived from transgenic mice expressing a tetracycline-regulated oncogene. Transgenic expression of several proteins implicated in the apoptotic pathways increase the resistance of betaTC-tet cells in vitro. We tested in vivo the sensitivity of the cells to rejection and the protective effect of genetic alterations in NOD mice.

METHODS

betaTC-tet cells and genetically engineered lines expressing Bcl-2 (CDM3D), a dominant negative mutant of MyD88 or SOCS-1 were transplanted in diabetic female NOD mice or in male NOD mice with diabetes induced by high-dose streptozotocin. Survival of functional cell grafts in NOD-scid mice was also analyzed after transfer of splenocytes from diabetic NOD mice. Autoreactive T-cell hybridomas and splenocytes from diabetic NOD mice were stimulated by betaTC-tet cells.

RESULTS

betaTC-tet cells and genetically engineered cell lines were all similarly rejected in diabetic NOD mice and in NOD-scid mice after splenocyte transfer. In 3- to 6-week-old male NOD mice treated with high-dose streptozotocin, the cells temporarily survived, in contrast with C57BL/6 mice treated with high-dose streptozotocin (indefinite survival) and untreated 3- to 6-week-old male NOD mice (rejection). The protective effect of high-dose streptozotocin was lost in older male NOD mice. betaTC-tet cells did not stimulate autoreactive T-cell hybridomas, but induced IL-2 secretion by splenocytes from diabetic NOD mice.

CONCLUSION/INTERPRETATION

The autoimmune process seems to play an important role in the destruction of betaTC-tet cells in NOD mice. Genetic manipulations intended at increasing the resistance of beta cells were inefficient. Similar approaches should be tested in vivo as well as in vitro. High dose streptozotocin influences immune rejection and should be used with caution.

Effect of gonadotropin-releasing hormone agonist treatment in boys with central precocious puberty: final height results

OBJECTIVE

The small number of boys present in most studies on final height (FH) after gonadotropin-releasing hormone agonist (GnRHa) treatment for central precocious puberty (CPP) offers difficulties in the evaluation of the effects of treatment on FH in males.

METHOD

We therefore combined FH data from The Netherlands, Italy and France to study the effect of GnRHa treatment in a large group of 26 boys with CPP.

RESULTS

The mean chronological age at the start of treatment was 7.6 +/- 2.0 (SD) years, bone age (BA) was 11.0 +/- 2.1 years. All boys were treated with depot formulations of the GnRHa triptorelin with established gonadal suppression for a mean treatment period of 4.7 +/- 2.1 years. FH was 172.9 +/- 6.6 cm. FH standard deviation score (SDS) was -0.66 +/- 1.22, not significantly different from the target height SDS of -0.23 +/- 0.75. FH-SDS was significantly lower in the subgroup of 12 patients with organic CPP compared to patients with idiopathic CPP (-1.34 +/- 1.06 vs. -0.08 +/- 1.06, respectively; p = 0.01), but no difference in height gain was observed. The mean estimated height gain, defined as the difference between predicted and actual adult height was 6.2 +/- 8.7 cm using the average tables of Bayley and Pinneau, and 0.3 +/- 8.6 cm using the BA advance adjusted tables. Regional differences in height gain were observed between the different countries, reflecting different local practices.

CONCLUSION

We conclude that GnRHa treatment in boys results in a FH close to target height.

[Two cases of mineralocorticoids deficiency as first endocrine manifestation of APECED syndrome]

The Authors report two cases of APECED syndrome (Auto-immune Polyendocrinopathy-Candidiasis-Ectodermal Dystrophy) revealed by hyponatremia due to isolated mineralocorticoids deficiency. Such cases illustrate the variable endocrine features revealing the syndrome. The mechanisms underlying the auto-immune destruction of the adrenals are discussed.

GNAS1 lesions in pseudohypoparathyroidism Ia and Ic: genotype phenotype relationship and evidence of the maternal transmission of the hormonal resistance

We conducted clinical and biological studies including screening for mutations in the gene encoding the alpha subunit of G(s) (GNAS1) in 30 subjects (21 unrelated families) with Albright's hereditary osteodystrophy (AHO), pseudohypoparathyroidism (PHP); and decreased erythrocyte G(s) activity (PHP-Ia; n = 19); AHO and decreased erythrocyte G(s) activity (isolated AHO; n = 10); or AHO, hormonal resistance, and normal erythrocyte G(s) activity (PHP-Ic; n = 1). A heterozygous GNAS1 gene lesion was found in 14 of 17 PHP-Ia index cases (82%), including 11 new mutations and a mutational hot-spot involving codons 189-190 (21%). These lesions lead to a truncated protein in all but three cases with missense mutations R280K, V159M, and D156N. In the patient diagnosed with PHP-Ic, G(s)alpha protein was shortened by just four amino acids, a finding consistent with the conservation of G(s) activity in erythrocytes and the loss of receptor contact. No GNAS1 lesions were found in individuals with isolated AHO that were not relatives to PHP-Ia patients (n = 5). Intrafamilial segregation analyses of the mutated GNAS1 allele in nine PHP-Ia patients established that the mutation had either occurred de novo on the maternal allele (n = 4) or had been transmitted by a mother with a mild phenotype (n = 5). This finding is consistent with an imprinting of GNAS1 playing a role in the clinical phenotype of loss of function mutations and with a functional maternal GNAS1 allele having a predominant role in preventing the hormonal resistance of PHP-Ia.

Effects of prolonged administration of ultralente insulin on fasting and postbreakfast beta-cell function in normal adults

Treatment with small doses of subcutaneous insulin is being investigated as a possible approach to prevent type 1 diabetes in humans. The mechanism of prophylactic insulin therapy could involve the inhibition of beta-cell secretory activity and/or the initiation of an active immunoregulatory process. To evaluate the pure metabolic effect of exogenous insulin, the present study assessed whether daily subcutaneous administration of ultralente insulin alters beta-cell function in normal adults. Fourteen healthy adults were randomized to receive 0.2 U/kg x d ultralente insulin (Ultratard; Novo Nordisk, Bagsvaerd, Denmark) or placebo subcutaneously once daily for 30 days. Plasma glucose, C-peptide, and insulin concentrations were measured in the fasting state and 1 hour after a standardized breakfast, during treatment and during a recovery period of 10 days. Insulin administration induced a 15% to 40% decrease of fasting plasma C-peptide. In contrast, postbreakfast plasma C-peptide increased by 40% to 90% in subjects receiving insulin. Fasting and postbreakfast C-peptide concentrations were significantly different between groups during the injection period after adjustment for baseline concentrations (P < .05, ANOVA with repeated measures). These alterations disappeared 3 days after cessation of insulin treatment. The present regimen of exogenous insulin alters endogenous insulin secretion in normal subjects. Instead of the expected beta-cell rest, the effect appeared to be dual, with insulin secretion decreasing in the basal state and increasing after meals.

Oral insulin administration and residual beta-cell function in recent-onset type 1 diabetes: a multicentre randomised controlled trial. Diabète Insuline Orale group

BACKGROUND

Oral administration of autoantigens can slow the progression of beta-cell destruction in non-obese diabetic mice. We investigated whether oral administration of recombinant human insulin could protect residual beta-cell function in recent-onset type 1 diabetes.

METHODS

We enrolled 131 autoantibody-positive diabetic patients aged 7-40 years within 2 weeks of diagnosis (no ketoacidosis at diagnosis, weight loss <10%, polyuria for <6 weeks). They were randomly assigned 2.5 mg or 7.5 mg oral insulin daily or placebo for 1 year, in addition to subcutaneous insulin therapy. Serum C-peptide concentrations were measured in the fasting state and after stimulation, to assess beta-cell function. Autoantibodies to beta-cell antigens were assayed. Analyses were by intention to treat.

FINDINGS

Baseline C-peptide and haemoglobin A1c concentrations were similar in the three groups. During follow-up, there were no differences between the groups assigned 2.5 mg or 7.5 mg oral insulin or placebo in subcutaneous insulin requirements, haemoglobin A1c concentrations, or measurements of fasting (mean at 12 months 0.18 [SD 0.17], 0.17 [0.17], and 0.17 [0.12] nmol/L) or stimulated C-peptide concentrations (glucagon-stimulated 0.39 [0.38], 0.37 [0.39], and 0.33 [0.24] nmol/L; meal-stimulated 0.72 [0.60], 0.49 [0.49], and 0.57 [0.51 nmol/L]. Neither age nor C-peptide concentration at entry influenced treatment effects. No differences were seen in the time-course or titres of antibodies to insulin, glutamic acid decarboxylase, or islet antigen 2.

INTERPRETATION

At the doses used in this trial, oral administration of insulin initiated at clinical onset of type 1 diabetes did not prevent the deterioration of beta-cell function.

Soluble leptin receptor in serum of subjects with complete resistance to leptin: relation to fat mass

Leptin resistance and obesity have been related to mutations of the leptin receptor gene in rodents and, recently, in a consanguineous family. The latter mutation results in a receptor lacking transmembrane and intracellular domains. Homozygous and heterozygous individuals with this mutation had serum leptin levels higher than expected, given their BMIs: 600, 670, and 526 ng/ml and 145, 362, 294, 240, and 212 ng/ml, respectively. Their serum leptin was fractionated by gel filtration: >80% was present as a high-molecular size complex vs. 7.5% in the nonmutated sister. Western blot analysis showed a band at 146 kDa reacting specifically with an antibody directed against the leptin receptor ectodomain. In 10 obese control subjects, as in the mutated patients, free leptin levels correlated with BMI (r = 0.70, P = 0.0011) and reflected fat mass, regardless of leptin receptor functioning. In the patients, bound leptin levels correlated with BMI (r = 0.99, P = 0.0002) and were related to the number of mutated alleles. These data demonstrate that the truncated receptor is secreted into blood and binds the majority of serum leptin, markedly increasing bound and total leptin. Free serum leptin was similarly correlated with BMI in the mutated and nonmutated obese individuals, providing evidence that the relationship between BMI and circulating free leptin is preserved in this family. This finding suggests that the leptin receptor itself may not be specifically involved in the control of leptin secretion, and it supports the concept of relative resistance to leptin in common obesity.

Pharmacokinetics and pharmacodynamics of GnRH agonists: clinical implications in pediatrics

Since 1981, GnRH agonist administration has been the treatment of choice for central precocious puberty. Continuous administration of the agonist, instead of permanently stimulating gonadotropin secretion, deeply suppresses LH and FSH levels and induces a marked inhibition of gonadal activity and regression of clinical symptoms. This inhibitory effect is due both to specific kinetic parameters relative to natural GnRH, and to marked alterations of the biosynthetic pathways of gonadotropin subunits. The half disappearance time of infused agonists is 3-10 fold that of natural GnRH. This means that the residence time of GnRH agonists is significantly longer than that of GnRH. The resistance of agonist to enzymatic degradation, mainly due to the substitution of a hydrophobic D-amino acid for glycine 6, is one of the factors involved in the increased availability of GnRH superagonists. The paradoxical effects of GnRH superagonists are still incompletely understood. In children long-term treated with depot formulations of triptorelin or leuprorelin, alpha-subunit secretion is markedly increased, and remains sensitive to exogenous GnRH, which demonstrates that the gonadotrophs are not totally desensitized. Despite the sustained stimulation of a-subunit secretion, no deleterious side effects, either during therapy or during post-therapy follow-up, have been reported in children treated with GnRH agonists. It should be noted that alpha-subunit responsiveness to exogenous GnRH decreases progressively after several years of treatment, although it is never completely abolished. On the other hand, LH beta-subunit secretion is suppressed as evidenced by radioimmunoassay of LH beta-subunit in serum chromatographic fractions from children treated with triptorelin. This differential pattern of secretion parallels that of mRNA levels in rat pituitary after in vivo exposure to triptorelin. Both pharmacodynamic and pharmacokinetic data can help diagnose the situations of resistance or escape. The lack of clinical effect of GnRH in the treatment of precocious puberty can be due to true resistance, or to an inappropriate injection schedule, or to abnormal metabolism. Measurement of serum alpha-subunit level, and, if needed, of serum agonist level, generally provides the answer.

[Growth hormone treatment of children with short stature secondary to intrauterine growth retardation]

There is now good evidence that short-term growth hormone treatment improves growth of children with short stature secondary to intrauterine growth retardation. A 3-year treatment with dosages greater than 1.2 U/kg/week allows these children to reach normal height, without any currently known side effect. Long-term efficacy, i.e., improvement of final height, is probable, but depends on the possibility of reconducting the treatment in case of loss of the initial benefits. The possible effect of treatment on puberty is presently unknown and will need special attention when treated children reach pubertal age.

[Catch-up growth in growth hormone deficit children treated with GH since the first year of life]

Long-term effects of growth hormone (GH) treatment were studied in 59 GH deficient (GHD) children, whose treatment was started before the age of 1 year, during the period 1978-1992, under the supervision of the France-Hypophyse Association. Mean duration of treatment was 8 +/- 3.6 years. At the last evaluation, 20 patients (34%) had a height above normal mean for age, and 50 (85%) had a height above the second lower standard deviation (SD) for age. Final height prediction performed in 29 patients was greater than target size (-0.35 +/- 1.4 SD vs -0.56 +/- 0.79 SD). These results show that early treatment of GHD infants allows normal statural growth in the majority of the cases; in addition, they underline the importance of early diagnosis of GH deficiency.

Gonadotropin releasing hormone agonist treatment for central precocious puberty

Several methodological problems complicate the evaluation of final statural height (FH) benefit after treatment with gonadotropin releasing hormone (GnRH) agonists for central precocious puberty (CPP). Since no controlled study has been performed, we have to rely on indirect methods, comparison with predicted height or with historical controls. FH of 58 girls, uniformly treated with triptorelin slow release formulation (triptorelin-SR, Decapeptyl((R))) for CPP were compared with predicted height before treatment and with FH of an historical group of patients not treated with GnRH agonist. The comparison with predicted height revealed an improvement of 4.8 +/- 5.8 cm; comparison with the historical control group showed a mean improvement of 8.3 cm. The post-treatment growth spurt (DeltaFH - height at the end of treatment) was a strong predictor of FH in multivariate analysis. The data suggest that continuing treatment beyond the age of 11 in girls does not improve and could actually decrease FH.

Resistance to the lipolytic action of epinephrine: a new feature of protein Gs deficiency

Deficiency of protein Gs (Gs; OMIM no.103580), the stimulatory regulator of adenylyl cyclase, is associated with resistance to PTH and other hormones, sc calcifications, short stature, and skeletal defects (Albright's hereditary osteodystrophy). It is caused by heterozygous loss of function mutations in GNAS 1, the gene encoding the alpha-subunit of Gs. Obesity is a classical feature of patients with Gs deficiency, but the mechanism leading to fat accumulation has not been elucidated. We measured glycerol flux, using a nonradioactive tracer dilution approach, to analyze the lipolytic response to epinephrine in 6 patients with Gs deficiency and PTH resistance and compared it to six age-matched normal controls and nine massively obese children. Basal glycerol production was reduced by 50%, and lipolytic response to epinephrine was reduced by 67%, in Gs-deficient children, as compared with controls. The degree of impairment of lipolysis was similar in Gs-deficient children who were only moderately overweight and in morbidly obese children. These findings extend the spectrum of hormonal resistance in Gs deficiency. Besides beta-adrenergic receptors, Gs protein itself should be examined as a possible step involved in the decreased lipolysis observed in common obesity.

Lack of effect of GnRH agonists on final height in girls with advanced puberty: a randomized long-term pilot study

GnRH agonists improve final height in girls with "true" precocious puberty. To test if a comparable effect can be obtained in older girls, we performed a long-term controlled study in 30 caucasian girls whose puberty started between 8.4 and 10 yr (9.4 +/- 0.1 yr), a variant of normal called "advanced" puberty. At entry into trial, these girls had clinical, biological, and sonographic manifestations of puberty and a bone age greater than 10.9 yr. They were randomized 2:1 to receive 3.75 mg triptorelin im every 4 weeks for 2 yr (n = 20, group I) or no treatment (n = 10, group II). Mean height at inclusion was 135.2 +/- 4.3 cm (+0.6 SDS) in group I, 136.1 +/- 4.2 cm (+0.8 SDS) in group II, with target height 157.6 +/- 4.3 cm (group I) and 157.8 +/- 4.7 cm (group II), and predicted height (Bayley-Pinneau) 154.1 +/- 3.9 cm and 155.2 +/- 3.7 cm. Although GnRH agonists transiently delayed sexual maturation as well as bone age and growth rate, they had no clear-cut long-standing effect, and final height was comparable in treated (157.6 +/- 4.0 cm) and untreated girls (156.1 +/- 5.3 cm) (NS).

Final height after long-term treatment with triptorelin slow release for central precocious puberty: importance of statural growth after interruption of treatment. French study group of Decapeptyl in Precocious Puberty

The impact of treatment of central precocious puberty (CPP) with GnRH agonists on final statural height (FH) remains controversial, and guidelines on the optimal time point for interruption of these treatments have not been established. We analyzed the long term results of 58 girls and 8 boys uniformly treated with triptorelin slow release formulation (Decapeptyl, triptorelin-SR) for CPP and compared their FH with predicted height before treatment and with the FH of a historical group of patients not treated with GnRH agonist. The FH SD score was close to 0 and was not different from the genetic target height. In girls, FH was improved by 4.8 +/- 5.8 cm compared with predicted height before treatment and by 8.3 cm by comparison with a historical group. In boys, comparison with a historical group revealed a 13.7-cm improvement, whereas predicted height before treatment was similar to FH. Three variables were independently associated with FH in girls: the bone age/statural age ratio at the onset of treatment (negatively), the height SD score at the end of treatment, and the posttreatment growth spurt (delta FH - height at the end of treatment). The influence of the posttreatment growth spurt, itself dependent on age and bone age at the interruption of treatment, suggests that continuing treatment beyond the age of 11 yr in girls does not improve and could actually decrease FH. This point should be evaluated in a formal controlled trial.

T-cell response to proinsulin and insulin in type 1 and pretype 1 diabetes

Insulin-dependent diabetes mellitus (IDDM) results from the selective destruction of pancreatic beta cells by a T cell-mediated autoimmune process. Insulin and proinsulin are the only known beta cell-specific autoantigens. Using short-term cultures of freshly isolated peripheral blood mononuclear cells, we evaluated T-cell responses to proinsulin and to insulin in IDDM patients and individuals at risk for IDDM. A proliferative T-cell response to proinsulin was observed in only 2 of 26 recent-onset IDDM subjects and 2 of 12 long-standing IDDM subjects and was associated with a proliferative response to insulin. In contrast, 5 of 13 islet cell autoantibody-positive first-degree relatives of IDDM patients showed a proliferative response to proinsulin alone, 3 of 13 to insulin alone, and 1 of 13 to both insulin and proinsulin. Overall, 9 of 13 ICA-positive first-degree relatives responded to either proinsulin or insulin. We observed an inverse relationship between antiinsulin antibodies and T-cell responses to insulin in ICA-positive first-degree relatives but not in long-standing IDDM patients. Our data indicate that proinsulin is a major antigen in IDDM and, further, illustrate the difference between the autoimmune response to insulin and the immune response to exogenous insulin.

Long-term results of GH therapy in GH-deficient children treated before 1 year of age

OBJECTIVES

To evaluate the long-term effects of GH therapy in early diagnosed GH-deficient patients treated before 1 year of age.

STUDY DESIGN

We studied all 59 patients (33 males) recorded by Association France-Hypophyse and treated with GH (0.50+/-0.15 IU/kg (S.D.) per week) before 1 year of age. Clinical presentation and growth parameters under GH treatment were analyzed.

RESULTS

Neonatal manifestations of hypopituitarism were frequent: hypoglycemia (n=50), jaundice (n=25) and micropenis (n=17/33). Although birth length was moderately reduced (-0.9+/-1.4), growth retardation at diagnosis (5.8+/-3.8 months) was severe (-3.5+/-1.9 standard deviation scores (SDS)). Fifty patients (85%) had thyrotropin and/or corticotropin deficiency. After a mean duration of GH therapy of 8.0+/-3.6 years, change in height SDS was +3.11+/-2.06 S.D., exceeding 4 SDS in 19 patients. Only 9 patients (15%) did not reach a height of -2 S.D. for chronological age and 20 patients (34%) exceeded their target height. Pretreatment height SDS was independently associated with total catch-up growth.

CONCLUSION

Conventional doses of GH allow normalization of height in patients with early GH deficiency and treatment.

Novel mutations in the thiazide-sensitive NaCl cotransporter gene in patients with Gitelman syndrome with predominant localization to the C-terminal domain

Gitelman syndrome (familial hypokalemia-hypomagnesemia syndrome) is an autosomal recessive inherited renal disorder characterized by defective tubular reabsorption of magnesium and potassium. In this study a group of 18 unrelated and 2 related Gitelman patients, collected from six different countries have been screened for mutations in the human thiazide-sensitive sodium-chloride cotransporter (SLC12A3) gene. Fourteen novel SLC12A3 mutations are presented along with six mutations described earlier, and three neutral polymorphisms. Among the tested patients are two who carry a total of three heterozygous SLC12A3 mutations. Two-thirds of the total number of mutant SLC12A3 alleles are amino acid substitutions. Most SLC12A3 gene mutations, 14 out of a total of 20, are localized at the intracellular carboxy-terminal domain of the NCCT protein. The pathogenicity of individual SLC12A3 mutations is based upon their predicted effect on SLC12A3 protein, and segregation in family members. Evolutionary conservation of substituted amino acid residues and their frequency in control chromosomes is presented. Identical mutations have been found in Gitelman families from different geographical origin, suggesting ancient mutations originating from a common ancestor. As yet, we have not found any evidence for a possible genotype-phenotype correlation.

Low dose linomide in Type I juvenile diabetes of recent onset: a randomised placebo-controlled double blind trial

The quinoline-3-carboxamide, linomide, protects non-obese diabetic mice from diabetes. The effects of linomide on insulin needs and beta cell function were studied in recent juvenile Type I diabetes in a double-blind trial. Patients with recent onset diabetes were randomly assigned to treatment with a fixed dose of 2.5 mg linomide (42 patients) or placebo (21 patients) for 1 year, in addition to insulin and diet. Glycated haemoglobin was 10-15% lower at 9 months (p = 0.003) and 12 months (p < 0.05) in the linomide group. The insulin dose was 32-40% smaller in the linomide group at 3 (p < 0.03), 6 (p < 0.02), 9 (p < 0.001) and 12 months (p = 0.01). Insulin doses correlated negatively with C peptide values (p = 0.001-0.002). The trend for higher C peptide values in the linomide group did not reach significance. In a post hoc subgroup analysis performed in 40 patients (25 from the linomide group and 15 from the placebo group) who still had detectable residual beta cell function at entry, linomide was associated with 45-59% higher C peptide value at 6 months (p < 0.05), 9 months (p < 0.05) and 12 months (p < 0.05). The main adverse effects of linomide were mild transitory anaemia (45 vs 10% in the linomide and placebo groups), thrombocytopenia (24 vs 10%), and mild joint discomfort (45 vs 5%) with no clinical signs. In conclusion, low-dose linomide reduced the insulin needs in patients with juvenile Type I diabetes of recent onset and improved beta cell function in patients who still had detectable beta cell function at entry. These results support further clinical and experimental studies to define the effects of linomide in Type I diabetes provided the safety of linomide is reliably established.

Factors associated with glycemic control. A cross-sectional nationwide study in 2,579 French children with type 1 diabetes. The French Pediatric Diabetes Group

OBJECTIVE

To determine on a large scale the multiple medical and nonmedical factors that influence glycemic control in the general population of children with diabetes, we performed a nationwide French cross-sectional study.

RESEARCH DESIGN AND METHODS

We enrolled 2,579 patients aged 1-19 years with type 1 diabetes of > 1 year's duration. The study was center based: 270 centers were identified, 206 agreed to participate, and 147 included at least 90% of their patients. Questionnaires were completed by physicians interviewing patients and family, and HbA1c measurements were centralized. To identify explanatory variables for HbA1c level and frequency of severe hypoglycemia, we performed multiple regression analysis using all the quantitative variables collected and stepwise logistic regression for the qualitative variables.

RESULTS

Mean HbA1c value for the whole population was 8.97 +/- 1.98% (normal 4.7 +/- 0.7% [SD]). Only 19 children (0.7%) had ketoacidosis during the 6 months before the study, whereas 593 severe hypoglycemia events occurred in 338 children (13.8%). Control was better in university-affiliated hospitals and centers following > 50 patients, reflecting the importance of access to experienced diabetologists. Children had a mean of 2.3 injections, allegedly performed 2.8 glucose measurements per day, and were seen an average of 4.6 times per year at the center. In the multiple regression analysis, 94% of the variance of HbA1c was explained by our pool of selected variables, with the highest regression coefficient between HbA1c and age (Rc = 0.43, P < 0.0001), then with daily insulin dosage per kilogram (Rc = 0.28, P < 0.0001), mother's age (Rc = 0.26, P < 0.0001), frequency of glucose measurements (Rc = 0.21, P < 0.0001), and diabetes duration (Rc = 0.14, P < 0.0001). Logistic regression identified quality of family support and dietary compliance, two related qualitative and possibly subjective variables, as additional explanatory determinants of HbA1c. The frequency of severe hypoglycemia was 45 per 100 patient-years and correlated with diabetes duration, but not with HbA1c levels or other variables.

CONCLUSIONS

Although overall results remain unsatisfactory, 33% of studied French children with type 1 diabetes had HbA1c < 8%, the value obtained in Diabetes Control and Complications Trial adolescents treated intensively. Diabetes management in specialized centers should be encouraged.