Enhancing fetal outcomes in GCK-MODY pregnancies: a precision medicine approach via non-invasive prenatal GCK mutation detection

Background

Mutations in the GCK gene cause Maturity Onset Diabetes of the Young (GCK-MODY) by impairing glucose-sensing in pancreatic beta cells. During pregnancy, managing this type of diabetes varies based on fetal genotype. Fetuses carrying a GCK mutation can derive benefit from moderate maternal hyperglycemia, stimulating insulin secretion in fetal islets, whereas this may cause macrosomia in wild-type fetuses. Modulating maternal glycemia can thus be viewed as a form of personalized prenatal therapy, highly beneficial but not justifying the risk of invasive testing. We therefore developed a monogenic non-invasive prenatal diagnostic (NIPD-M) test to reliably detect the transmission of a known maternal GCK mutation to the fetus.

Methods

A small amount of fetal circulating cell-free DNA is present in maternal plasma but cannot be distinguished from maternal cell-free DNA. Determining transmission of a maternal mutation to the fetus thus implies sequencing adjacent polymorphisms to determine the balance of maternal haplotypes, the transmitted haplotype being over-represented in maternal plasma.

Results

Here we present a series of such tests in which fetal genotype was successfully determined and show that it can be used to guide therapeutic decisions during pregnancy and improve the outcome for the offspring. We discuss several potential hurdles inherent to the technique, and strategies to overcome these.

Conclusion

Our NIPD-M test allows reliable determination of the presence of a maternal GCK mutation in the fetus, thereby allowing personalized in utero therapy by modulating maternal glycemia, without incurring the risk of miscarriage inherent to invasive testing.

Noninvasive prenatal diagnosis of Mendelian disorders for consanguineous couples by relative genotype dosage

Noninvasive prenatal diagnosis relies on the presence in maternal blood of circulating cell-free fetal DNA released by apoptotic trophoblast cells. Widely used for aneuploidy screening, it can also be applied to monogenic diseases (NIPD-M) in case of known parental mutations. Due to the confounding effect of maternal DNA, detection of maternal or biparental mutations requires relative haplotype dosage (RHDO), a method relying on the presence of SNPs that are heterozygous in one parent and homozygous in the other. Unavoidably, there is a risk of test failure by lack of such informative SNPs, an event particularly likely for consanguineous couples who often share common haplotypes in regions of identity-by-descent. Here we present a novel approach, relative genotype dosage (RGDO) that bypasses this predicament by directly assessing fetal genotype with SNPs that are heterozygous in both parents (frequent in regions of identity-by-descent). We show that RGDO is as sensitive as RHDO and that it performs well over a large range of fetal fractions and DNA amounts, thereby opening NIPD-M to most consanguineous couples. We also report examples of couples, consanguineous or not, where combining RGDO and RHDO allowed a diagnosis that would not have been possible with only one approach.

[Obesity in infancy: new precision treatment]

Obesity is a chronical disease, which leads to multiple short- and long-term complications. 4% of Swiss children and adolescents are obese. A prompt diagnosis and multicomponent lifestyle intervention is mandatory to avoid persistence of the disease into adulthood. Growth and BMI charts are still the essential tools to diagnose and define the etiology of obesity. A precocious and severe obesity, accompanied by hyperphagia, will raise the suspicion of monogenic obesity. The precise molecular diagnosis enables in some patients the use of a specific treatment. Leptine in case of LEP gene defects, or setmelanotide when the affected gene is part of the MC4R signaling pathway (LEPR, POMC, PCSK1).

[Monogenic diabetes : a pioneer in precision medicine management]

Diabetes mellitus in children is subdivided into several categories depending on the underlying pathological mechanism. Type 1 diabetes is due to the autoimmune destruction of pancreatic beta-cells, type 2 diabetes to progressive impairment in insulin secretion or insulin sensitivity, and monogenic diabetes due to genetic abnormalities, impairing insulin secretion. In monogenic diabetes, genetic defects result in pancreatic or beta-cell defects (abnormal function or destruction), resulting in neonatal or MODY (Maturity-Onset Diabetes of the Young) diabetes, depending on the age of onset. The identification of monogenic diabetes is crucial as it allows the initiation of targeted and personalized treatment.

Hepatic non-parenchymal S100A9-TLR4-mTORC1 axis normalizes diabetic ketogenesis

Unrestrained ketogenesis leads to life-threatening ketoacidosis whose incidence is high in patients with diabetes. While insulin therapy reduces ketogenesis this approach is sub-optimal. Here, we report an insulin-independent pathway able to normalize diabetic ketogenesis. By generating insulin deficient male mice lacking or re-expressing Toll-Like Receptor 4 (TLR4) only in liver or hepatocytes, we demonstrate that hepatic TLR4 in non-parenchymal cells mediates the ketogenesis-suppressing action of S100A9. Mechanistically, S100A9 acts extracellularly to activate the mechanistic target of rapamycin complex 1 (mTORC1) in a TLR4-dependent manner. Accordingly, hepatic-restricted but not hepatocyte-restricted loss of Tuberous Sclerosis Complex 1 (TSC1, an mTORC1 inhibitor) corrects insulin-deficiency-induced hyperketonemia. Therapeutically, recombinant S100A9 administration restrains ketogenesis and improves hyperglycemia without causing hypoglycemia in diabetic mice. Also, circulating S100A9 in patients with ketoacidosis is only marginally increased hence unveiling a window of opportunity to pharmacologically augment S100A9 for preventing unrestrained ketogenesis. In summary, our findings reveal the hepatic S100A9-TLR4-mTORC1 axis in non-parenchymal cells as a promising therapeutic target for restraining diabetic ketogenesis.

Excess ketogenesis can lead to ketoacidosis, a serious complication in patients with diabetes. Here the authors report an insulin independent pathway, the hepatic nonparenchymal S100A9-TLR4-mTORC1 axis, that is able to normalize diabetic ketogenesis and pre-clinical data to suggest potential for development of S100A9 based adjunctive therapy to insulin.

[MODY type diabetes: an often-misunderstood entity]

MODY diabetes, for Maturity Onset Diabetes of the Young, is a form of monogenic diabetes characterized by a typical onset before the age of 25 years, the lack of autoimmunity against the b cells of the pancreas, a preserved β cells function and an autosomal dominant mode of inheritance. This type of diabetes constitutes 2 to 5% of all cases of diabetes but remains often undiagnosed. Nearly 15 MODY subtypes have been identified to date. The 3 most common subtypes are caused by mutations in the genes encoding glucokinase, HNF1a and HNF4a, and account for approximately 80% of all MODY cases. Carrying out a genetic test can thus make it possible to make the diagnosis of MODY diabetes and to set up an appropriate treatment. In this article we will discuss these 3 main MODY sub-type, although there are other forms, which may be characterized by associated specific organ damage.

Activation of Nicotinic Acetylcholine Receptors Decreases Apoptosis in Human and Female Murine Pancreatic Islets

Type 1 diabetes (T1DM) results from destruction of most insulin-secreting pancreatic β-cells. The persistence of β-cells decades after the onset of the disease indicates that the resistance of individual cells to the autoimmune insult is heterogeneous and might depend on the metabolic status of a cell at a given moment. The aim of this study is to investigate whether activation of nicotinic acetylcholine receptors (nACh-Rs) could increase β-cell resistance against the adverse environment prevailing at the onset of T1DM. Here, we show that nACh-R activation by nicotine and choline, 2 agonists of the receptor, decreases murine and human β-cell apoptosis induced by proinflammatory cytokines known to be present in the islet environment at the onset of T1DM. The protective mechanism activated by nicotine and choline involves attenuation of mitochondrial outer membrane permeabilization via modulation of endoplasmic reticulum stress, of the activity of B-cell lymphoma 2 family proteins and cytoplasmic calcium levels. Local inflammation and endoplasmic reticulum stress being key determinants of β-cell death in T1DM, we conclude that pharmacological activation of nACh-R could represent a valuable therapeutic option in the modulation of β-cell death in T1DM.

Widespread intracranial calcifications in the follow-up of a patient with cartilage-hair hypoplasia--anauxetic dysplasia spectrum disorder: a coincidental finding?

BACKGROUND/PURPOSE

Intracranial calcifications have been identified in many neurological disorders. To our knowledge, however, such findings have not been described in cartilage-hair hypoplasia - anauxetic dysplasia spectrum disorders (CHH-AD), a group of conditions characterized by a wide spectrum of clinical manifestations.

METHODS/RESULTS

We report a 22-year old female patient, diagnosed with this disorder during her first year of life, and in whom bilateral intracranial calcifications (frontal lobes, basal ganglia, cerebellar dentate nuclei) were discovered by brain MRI at the age of 17 years.

CONCLUSION

The etiology of this finding remains unclear. Some causes of such deposits can be of a reversible nature, thus prompting early recognition although their consequences on clinical outcome remain mostly unknown.

Diabetes and immune thrombocytopenic purpura: a new association with good response to anti-CD20 therapy

Type 1 diabetes (T1D) is rarely a component of primary immune dysregulation disorders. We report two cases in which T1D was associated with thrombocytopenia. The first patient, a 13-year-old boy, presented with immune thrombocytopenia (ITP), thyroiditis, and, 3 wk later, T1D. Because of severe thrombocytopenia resistant to immunoglobulins, high-dose steroids, and cyclosporine treatment, anti-cluster of differentiation (CD20) therapy was introduced, with consequent normalization of thrombocytes and weaning off of steroids. Three and 5 months after anti-CD20 therapy, levothyroxin and insulin therapy, respectively, were stopped. Ten months after stopping insulin treatment, normal C-peptide and hemoglobin A1c (HbA1c) levels and markedly reduced anti-glutamic acid decarboxylase (GAD) antibodies were measured. A second anti-CD20 trial for relapse of ITP was initiated 2 yr after the first trial. Anti-GAD antibody levels decreased again, but HbA1c stayed elevated and glucose monitoring showed elevated postprandial glycemia, demanding insulin therapy. To our knowledge, this is the first case in which insulin treatment could be interrupted for 28 months after anti-CD20 treatment. In patient two, thrombocytopenia followed a diagnosis of T1D 6 yr previously. Treatment with anti-CD20 led to normalization of thrombocytes, but no effect on T1D was observed. Concerning the origin of the boys' conditions, several primary immune dysregulation disorders were considered. Thrombocytopenia associated with T1D is unusual and could represent a new entity. The diabetes manifestation in patient one was probably triggered by corticosteroid treatment; regardless, anti-CD20 therapy appeared to be efficacious early in the course of T1D, but not long after the initial diagnosis of T1D, as shown for patient two.

[Transition in diabetology]

For patients with type I diabetes, transition from pediatric to adult care is a challenge due to complex treatment requirements and the physical, psychological and social changes of adolescence. Members of the care team must recognize that while these emerging adults need to develop self-management skills, this may conflict at times with the developmentally appropriate desire for increasing autonomy. The role of nursing in coordinating a successful transition is critical for maintaining continuity of patient-centered care that responds to the specific needs of these young adults.

Concomitant alpha7 and beta2 nicotinic AChR subunit deficiency leads to impaired energy homeostasis and increased physical activity in mice

Nicotinic acetylcholine receptors (nAChRs) are pentameric ligand-gated cation channels well characterized in neuronal signal transmission. Moreover, recent studies have revealed nAChR expression in nonneuronal cell types throughout the body, including tissues involved in metabolism. In the present study, we screen gene expression of nAChR subunits in pancreatic islets and adipose tissues. Mice pancreatic islets present predominant expression of α7 and β2 nAChR subunits but at a lower level than in central structures. Characterization of glucose and energy homeostasis in α7β2nAChR(-/-) mice revealed no major defect in insulin secretion and sensitivity but decreased glycemia apparently unrelated to gluconeogenesis or glycogenolysis. α7β2nAChR(-/-) mice presented an increase in lean and bone body mass and a decrease in fat storage with normal body weight. These observations were associated with elevated spontaneous physical activity in α7β2nAChR(-/-) mice, mainly due to elevation in fine vertical (rearing) activity while their horizontal (ambulatory) activity remained unchanged. In contrast to α7nAChR(-/-) mice presenting glucose intolerance and insulin resistance associated to excessive inflammation of adipose tissue, the present metabolic phenotyping of α7β2nAChR(-/-) mice revealed a metabolic improvement possibly linked to the increase in spontaneous physical activity related to central β2nAChR deficiency.

A novel SRY mutation leads to asymmetric SOX9 activation and is responsible for mixed 46,XY gonadal dysgenesis

BACKGROUND

SRY, located on the Y chromosome, is one of the key genes involved in human sex determination. SRY mutations are responsible for 10-15% of all cases of 46,XY gonadal dysgenesis (GD) but are rarely implicated in the pathogenesis of mixed GD.

METHODS

SRY was analyzed by sequence analysis of DNA extracted from blood leukocytes. SRY activity was evaluated by SOX9 immunostaining, one of the targets of SRY.

RESULTS

We report a case of mixed GD due to a novel SRY point mutation in a patient with a 46,XY karyotype, without mosaicism or submicroscopic genomic imbalances. Hormonal studies showed low anti-müllerian hormone and histological examination of the gonads showed a streak gonad on the right side and a left dysgenetic testis, thus permitting the diagnosis of mixed GD. Immunostaining for SOX9, a target of SRY, was positive in nuclei of Sertoli and epididymal cells in the left gonad and negative on the right, thus indicating asymmetric activation of SRY.

CONCLUSION

Mixed GD can result from SRY mutations without mosaicism, neither in peripheral blood, nor within the gonads. The asymmetric effect of the point mutation implies the presence of local factors modulating SRY expression or action.

Early metabolic defects in dexamethasone-exposed and undernourished intrauterine growth restricted rats

Poor fetal growth, also known as intrauterine growth restriction (IUGR), is a worldwide health concern. IUGR is commonly associated with both an increased risk in perinatal mortality and a higher prevalence of developing chronic metabolic diseases later in life. Obesity, type 2 diabetes or metabolic syndrome could result from noxious “metabolic programming.” In order to better understand early alterations involved in metabolic programming, we modeled IUGR rat pups through either prenatal exposure to synthetic glucocorticoid (dams infused with dexamethasone 100 µg/kg/day, DEX) or prenatal undernutrition (dams feeding restricted to 30% of ad libitum intake, UN). Physiological (glucose and insulin tolerance), morphometric (automated tissue image analysis) and transcriptomic (quantitative PCR) approaches were combined during early life of these IUGR pups with a special focus on their endocrine pancreas and adipose tissue development. In the absence of catch-up growth before weaning, DEX and UN IUGR pups both presented basal hyperglycaemia, decreased glucose tolerance, and pancreatic islet atrophy. Other early metabolic defects were model-specific: DEX pups presented decreased insulin sensitivity whereas UN pups exhibited lowered glucose-induced insulin secretion and more marked alterations in gene expression of pancreatic islet and adipose tissue development regulators. In conclusion, these results show that before any catch-up growth, IUGR rats present early physiologic, morphologic and transcriptomic defects, which can be considered as initial mechanistic basis of metabolic programming.

Electrogastrography abnormalities appear early in children with diabetes type 1

OBJECTIVE

The objective of the study was to evaluate gastric myoelectrical activity in young patients with diabetes and to correlate it with their metabolic control [fasting blood glucose, glycosylated haemoglobin, and fructosamine] and BMI during a 3 years follow-up.

METHODS

Surface electrogastrography (EGG) was performed on 49 children with diabetes aged 10.3±4.4 (mean±SD) years and 17 age-matched healthy controls after fasting glucose, glycosylated haemoglobin, and fructosamine were measured. EGG parameters [percentage of bradygastria, 3 cycles per minute, tachygastria, dominant frequency instability coefficient, and power ratio] were analysed and compared with blood analysis.

RESULTS

Patients with diabetes exhibited an increase in preprandial bradygastria 7.9±8.8 cpm (mean±SD) compared with controls 2.1±1.0 (P=0.011), with an associated decrease in preprandial normogastria (72.2±14.5 vs. 82.7±14.7; P=0.013). Normogastric power ratio (postprandial/ preprandial power) was significantly increased in the children with diabetes compared with controls (mean: 6.67 vs. 3.14, P=0.034). A longer duration of diabetes was associated with an increased risk of EGG abnormalities (P=0.036). Marked hyperglycaemia at the time of study was associated with postprandial bradygastria (P=0.01) and power ratio bradygastria (P=0.042). Changes in glycosylated haemoglobin, fructosamine and BMI did not affect EGG parameters.

CONCLUSIONS

EGG abnormalities, presented early in a high proportion of diabetic children, are related to the acute hyperglycaemia. These abnormalities are not consistently present in the follow-up studies and not related to the glycosylated haemoglobin and fructosamine. Diabetic autonomic neuropathy is therefore an unlikely pathogenic factor for EGG abnormalities in children with diabetes.

[Current and future care for diabetes in children: from insulin to immunotherapy]

Diabetes type I (DTI) is an autoimmune disease characterized by a progressive destruction of the insulin producing beta cells of the pancreas that requires insulin substitution therapy. Recent epidemiological data show an annual increase of the incidence of DTI of 3.9%. Children with new onset diabetes typically present with polyuria, polydipsia and weight loss. As of today no cure for DTI exists. However new therapeutic immunomodulary approaches are under investigation. In the meantime adherence to insulin therapy is mandatory to achieve near physiological glucose levels. Monogenic forms of diabetes remain rare in children, but their diagnosis is important in order to propose a specific treatment. A critical period for the diabetic patient is the transition from pediatric to adult care.

Aplasia cutis congenita in surviving co-twin after propylthiouracil exposure in utero

AIM

Aplasia cutis congenita (ACC) has been observed after fetal exposure to the antithyroid drug methimazole (MMI), but not reported after propylthiouracil (PTU), the current antithyroid drug of choice during pregnancy. This occurrence has implications for patient information and causal research.

CASE REPORT

We describe a surviving term co-twin to a mother with hyperthyroidism exposed to PTU from conception to 34 weeks of gestation presenting with ACC at birth.

DISCUSSION

The association between PTU exposure and ACC is clinically relevant and allows speculation on the etiology. A similar mechanism to the classical MMI-induced ACC is postulated, unless a vascular etiology suggested by a vanishing twin or maternal hyperthyroidism itself is causal. Coincidence of PTU exposure and ACC seems unlikely.

CONCLUSION

ACC in a newborn after PTU exposure during pregnancy hitherto observed only after MMI strongly encourages further reports of similar cases that may remain clinically underdiagnosed or unreported. Such confirmation could have significant implications for maternal treatment of hyperthyroidism, common in women of childbearing age.

Perinatal exposure to bisphenol a alters early adipogenesis in the rat

BACKGROUND

The causes of the current obesity pandemic have not been fully elucidated. Implication of environmental endocrine disruptors such as bisphenol A (BPA) on adipose tissue development has been poorly investigated.

OBJECTIVES

The aim of the present study was to evaluate the effects of perinatal exposure to BPA on early adipose storage at weaning.

METHODS

Pregnant Sprague-Dawley rats had access to drinking water containing 1 mg/L BPA from day 6 of gestation through the end of lactation. Pups were weaned on postnatal day (PND) 21. At that time, we investigated perigonadal adipose tissue of pups (weight, histology, gene expression). For the remaining animals, we recorded body weight and food intake for animals on either standard chow or a high-fat diet.

RESULTS

Gestational exposure to BPA did not alter the sex ratio or litter size at birth. On PND1, the weight of male and female BPA-exposed pups was increased. On PND21, body weight was increased only in females, in which parametrial white adipose tissue (pWAT) weight was increased about 3-fold. This excess of pWAT was associated with adipocyte hypertrophy and overexpression of lipogenic genes such as C/EBP-alpha (CAAT enhancer binding protein alpha), PPAR-gamma (peroxisome proliferator-activated receptor gamma), SREBP-1C (sterol regulatory element binding protein-1C), LPL (lipoprotein lipase), FAS (fatty acid synthase), and SCD-1 (stearoyl-CoA desaturase 1). In addition, gene expression of SREBP-1C, FAS, and ACC (acetyl-CoA carboxylase) was also increased in liver from BPA-exposed females at PND21, without a change in circulating lipids and glucose. After weaning, perinatal BPA exposure predisposed to overweight in a sex- and diet-dependent manner. We observed no change in food intake due to perinatal BPA exposure in rats on either standard chow or a high-fat diet.

CONCLUSIONS

Perinatal exposure to a low dose of BPA increased adipogenesis in females at weaning. Adult body weight may be programmed during early life, leading to changes dependent on the sex and the nutritional status. Although further studies are required to understand the mechanisms of BPA action in early life, these results are particularly important with regard to the increasing prevalence of childhood obesity and the context-dependent action of endocrine disruptors.

Modeling intrauterine growth retardation in rodents: Impact on pancreas development and glucose homeostasis

Fetal adverse environment, such as insufficient maternal nutrition, placental insufficiency and stress, alters organ development and leads to poor fetal growth, also called intrauterine growth retardation (IUGR). IUGR is associated with an increased risk of perinatal mortality and morbidity as well as late-onset metabolic diseases, such as obesity, diabetes and hypertension in adulthood. In the rodent model, IUGR can be induced by fetal caloric restriction, fetal protein restriction, by exposure to high levels of glucocorticoids or by restricted placental blood supply. Such experimental IUGR models show a decreased beta cell mass and lower pancreatic insulin content. Recent research has provided an insight into the mechanisms responsible for the loss of beta cells. Here we review models that give further details about the molecular determinants of fetal and postnatal pancreatic islet development that are required to understand the consequences of fetal insults.

Prenatal nicotine exposure and the programming of metabolic and cardiovascular disorders

Presently, a growing interest is focused on the origins of the "Metabolic Syndrome", a cluster of several metabolic disorders linking obesity, dyslipidemia, hypertension and type 2 diabetes mellitus. Clearly, genetic predisposition and deleterious lifestyle, including low physical activity and hypercaloric alimentation, have an influence on the occurrence of the Metabolic Syndrome. However, recent data suggest that the Metabolic Syndrome could also be "programmed" during intrauterine life by diverse insults to the growing foetus. Nicotine is the main stimulant and dependence-forming alkaloid found in tobacco, and despite medical advice, statistics show that 20-30% of female smokers continue the habit during gestation, representing around 10% of all pregnancies. In consequence, nicotine is one of the most universally dangerous chemicals to which developing foetuses are exposed. The present review focuses on recent epidemiological surveys and experimental animal studies that provide evidences indicating that pre- and postnatal nicotine exposure might be a contributing factor for the occurrence of metabolic disorders later in life.

Prenatal nicotine exposure alters early pancreatic islet and adipose tissue development with consequences on the control of body weight and glucose metabolism later in life

Despite medical advice, 20-30% of female smokers continue to smoke during pregnancy. Epidemiological studies have associated maternal smoking with increased risk of obesity and type-2 diabetes in the offspring. In the present study, we investigated the impact of prenatal nicotine exposure (3 mg/kg in Sprague Dawley rats via osmotic Alzet minipumps) on the early endocrine pancreas and adipose tissue development in rat pups before weaning. Body weight, fat deposition, food intake and food efficiency, cold tolerance, spontaneous physical activity, glucose utilization, and insulin sensitivity were also examined at adulthood. Prenatal nicotine exposure led to a decrease in endocrine pancreatic islet size and number at 7 d of life (postnatal d 7), which corroborates with a decrease in gene expression of specific transcription factors such as pancreatic and duodenal homeobox 1, Pax-6, Nkx6.1, and of hormones such as insulin and glucagon. The prenatal nicotine exposure also led to an increase in epididymal white adipose tissue weight at weaning (postnatal d 21), and marked hypertrophy of adipocytes, with increased gene expression of proadipogenic transcription factors such as CAAT-enhancer-binding protein-alpha, peroxisome proliferator activated receptor-gamma, and sterol regulatory element binding protein-1C. These early tissue alterations led to significant metabolic consequences, as shown by increased body weight and fat deposition, increased food efficiency on high-fat diet, cold intolerance, reduced physical activity, and glucose intolerance combined with insulin resistance observed at adulthood. These results prove a direct association between fetal nicotine exposure and offspring metabolic syndrome with early signs of dysregulations of adipose tissue and pancreatic development.

[The diabetic child and the specifics of insulin therapy]

The incidence of diabetes type I has increased considerably in young children with an annual increase in Switzerland of 23,8% over the last ten years. The development of rapid acting and long acting analogues allowed a significant progress in treatment. Multiple daily insulin injections together with carbohydrate counting as well as continuous subcutaneous insulin infusion (CSII) improved the quality of life and led to an increased daily flexibility. The incidence of severe hypoglycaemic events has decreased at the same time metabolic control improved. The development of interstitial glucose measurement (online) coupled to the insulin pump represents a step further towards the artificial pancreas. The new therapeutic strategies of immunomodulation will hopefully lead to secondary and tertiary prevention of diabetes.

[Diabetes type 2 in pediatrics: diagnosis and management]

Our way of life has led to a massive increase in the prevalence of obesity in adults and children. Therefore diabetes type 2 has also become a pediatric disease. Therapy consists above all of implementing modifications of life style such as a healthy diet and regular physical activity in order to achieve a decrease in body weight. If these measurements prove to be insufficient, medical treatments are introduced, either using metformine or insulin. The screening and treatment of complications (retinopathy, nephropathy) and comorbidities (arterial hypertension, dyslipidemia) will help to decrease mortality on the long haul.

[Epigenetic origin of diabetes and growth disorders]

The understanding of genomic imprinting has made us realize that maternal and paternal contributions to the embryo are different. Disturbances during the imprinting process may lead to different pathologies due to an imbalance of gene expression either maternally or paternally derived. Known epigenetic diseases such as neonatal diabetes, growth retardation or overgrowth syndromes as well as cancer are better understood. It has become clear that environmental factors can be at the origin of such epigenetic changes. Careful analysis and diagnosis of epigenetic diseases are important for patient treatment and outcome.

The Zinc Finger-Containing Transcription Factor Gata-4 Is Expressed in the Developing Endocrine Pancreas and Activates Glucagon Gene Expression

Gene inactivation studies have shown that members of the Gata family of transcription factors are critical for endoderm development throughout evolution. We show here that Gata-4 and/or Gata-6 are not only expressed in the adult exocrine pancreas but also in glucagonoma and insulinoma cell lines, whereas Gata-5 is restricted to the exocrine pancreas. During pancreas development, Gata-4 is expressed already at embryonic d 10.5 and colocalizes with early glucagon+ cells at embryonic d 12.5. Gata-4 was able to transactivate the glucagon gene both in heterologous BHK-21 (nonislet Syrian baby hamster kidney) and in glucagon-producing InR1G9 cells. Using gel-mobility shift assays, we identified a complex formed with nuclear extracts from InR1G9 cells on the G5 control element (−140 to −169) of the glucagon gene promoter as Gata-4. Mutation of the GATA binding site on G5 abrogated the transcriptional activation mediated by Gata-4 and reduced basal glucagon gene promoter activity in glucagon-producing cells by 55%. Furthermore, Gata-4 acted more than additively with Forkhead box A (hepatic nuclear factor-3) to trans-activate the glucagon gene promoter. We conclude that, besides its role in endoderm differentiation, Gata-4 might be implicated in the regulation of glucagon gene expression in the fetal pancreas and that Gata activity itself may be modulated by interactions with different cofactors.

Programming of the pancreas

The pancreas, as most of the digestive tract, derives from the endoderm. Differentiation of these early gut endoderm cells into the endocrine cells forming the pancreatic islets of Langerhans depends on a cascade of gene activation events. These are controlled by different classes of transcription factors including the homeodomain, the basic helix-loop-helix (bHLH) and the winged helix proteins. Recently, considerable progress has been made delineating this cascade. The present review focuses on the role of the different transcription factors during pancreas development, with a particular emphasis on the newly identified bHLH transcription factor neurogenin3.

Expression of neurogenin3 reveals an islet cell precursor population in the pancreas

Differentiation of early gut endoderm cells into the endocrine cells forming the pancreatic islets of Langerhans depends on a cascade of gene activation events controlled by transcription factors including the basic helix-loop-helix (bHLH) proteins. To delineate this cascade, we began by establishing the position of neurogenin3, a bHLH factor found in the pancreas during fetal development. We detect neurogenin3 immunoreactivity transiently in scattered ductal cells in the fetal mouse pancreas, peaking at embryonic day 15.5. Although not detected in cells expressing islet hormones or the islet transcription factors Isl1, Brn4, Pax6 or PDX1, neurogenin3 is detected along with early islet differentiation factors Nkx6.1 and Nkx2.2, establishing that it is expressed in immature cells in the islet lineage. Analysis of transcription factor-deficient mice demonstrates that neurogenin3 expression is not dependent on neuroD1/BETA2, Mash1, Nkx2.2, Nkx6.1, or Pax6. Furthermore, early expression of neurogenin3 under control of the Pdx1 promoter is alone sufficient to drive early and ectopic differentiation of islet cells, a capability shared by the pancreatic bHLH factor, neuroD1/BETA2, but not by the muscle bHLH factor, MyoD. However, the islet cells produced in these transgenic experiments are overwhelmingly (alpha) cells, suggesting that factors other than the bHLH factors are required to deviate from a default * cell fate. These data support a model in which neurogenin3 acts upstream of other islet differentiation factors, initiating the differentiation of endocrine cells, but switching off prior to final differentiation. The ability to uniquely identify islet cell precursors by neurogenin3 expression allows us to determine the position of other islet transcription factors in the differentiation cascade and to propose a map for the islet cell differentiation pathway.

Normal female infants born of mothers with classic congenital adrenal hyperplasia due to 21-hydroxylase deficiency

Women with congenital adrenal hyperplasia due to 21-hydroxylase deficiency, especially those patients with the salt-losing form, have decreased fertility rates. Pregnancy experience in this population is limited. We report the pregnancy outcomes and serial measurements of maternal serum steroid levels in four women with classic 21-hydroxylase deficiency, three of whom were female pseudohermaphrodites with the salt-losing form. These glucocorticoid-treated women gave birth to four healthy female newborns with normal female external genitalia, none of whom were affected with 21-hydroxylase deficiency. In three women, circulating androgen levels increased during gestation, but remained within the normal range for pregnancy during glucocorticoid therapy. In the fourth patient, androgen levels were strikingly elevated during gestation despite increasing the dose of oral prednisone from 5 to 15 mg/day (two divided doses). Notwithstanding the high maternal serum concentration of androgens, however, placental aromatase activity was sufficient to prevent masculinization of the external genitalia of the female fetus and quite likely the fetal brain, consistent with the idea that placental aromatization of androgens to estrogens is the principal mechanism that protects the female fetus from the masculinizing effects of maternal hyperandrogenism. These four patients highlight key issues in the management of pregnancy in women with 21-hydroxylase deficiency, particularly the use of endocrine monitoring to assess adrenal androgen suppression in the mother, especially when the fetus is female. Recommendations for the management of pregnancy and delivery in these patients are discussed.

Neonatal hyperinsulinism

Hyperinsulinism is the most frequent cause of severe, persistent hypoglycemia in neonates and young infants. Timely diagnosis and aggressive treatment are necessary to prevent long-term neurologic sequelae. This article explores the latest advances in the understanding of the pathophysiology of this disorder at the molecular and cellular level. The clinical features, hallmarks for diagnosis, and various treatment options are discussed.