A novel NEUROG3 mutation in neonatal diabetes associated with a neuro-intestinal syndrome.

Neonatal diabetes mellitus (NDM) is a rare form of non-autoimmune diabetes usually diagnosed in the first 6 months of life. Various genetic defects have been shown to cause NDM with diverse clinical presentations and variable severity. Among transcriptional factor genes associated with isolated or syndromic NDM, a few cases of homozygous mutations in the NEUROG3 gene have been reported, all mutated patients presenting with congenital malabsorptive diarrhea with or without diabetes at a variable age of onset from early life to childhood. Through a targeted next-generation sequencing assay for monogenic diabetes genes, we aimed to search for pathogenic deleterious mutation in a Turkish patient with NDM, severe malabsorptive diarrhea, neurointestinal dysplasia and other atypical features. In this patient, we identified a novel homozygous nonsense mutation (p.Q4*) in NEUROG3. The same biallelic mutation was found in another affected family member. Of note, the study proband presents with abnormalities of the intrahepatic biliary tract, thyroid gland and central nervous system, which has never been reported before in NEUROG3 mutation carriers. Our findings extend the usually described clinical features associated with NEUROG3 deficiency in humans, and question the extent to which a complete lack of NEUROG3 expression may affect pancreas endocrine function in humans.

Targets and teamwork: Understanding differences in pediatric diabetes centers treatment outcomes.

OBJECTIVE: The reason for center differences in metabolic control of childhood diabetes is still unknown. We sought to determine to what extent the targets, expectations, and goals that diabetes care professionals have for their patients is a determinant of center differences in metabolic outcomes. RESEARCH DESIGN AND METHODS: Children, under the age of 11 with type 1 diabetes and their parents treated at the study centers participated. Clinical, medical, and demographic data were obtained, along with blood sample for centralized assay. Parents and all members of the diabetes care team completed questionnaires on treatment targets for hemoglobin A1c (HbA1c) and recommended frequency of blood glucose monitoring. RESULTS: Totally 1113 (53% male) children (mean age 8.0 ± 2.1 years) from 18 centers in 17 countries, along with parents and 113 health-care professionals, participated. There were substantial differences in mean HbA1c between centers ranging from 7.3 ± 0.8% (53 mmol/mol ± 8.7) to 8.9 ± 1.1% (74 mmol/mol ± 12.0). Centers with lower mean HbA1c had (1) parents who reported lower targets for their children, (2) health-care professionals that reported lower targets and more frequent testing, and (3) teams with less disagreement about recommended targets. Multiple regression analysis indicated that teams reporting higher HbA1c targets and more target disagreement had parents reporting higher treatment targets. This seemed to partially account for center differences in Hb1Ac. CONCLUSIONS: The diabetes care teams' cohesiveness and perspectives on treatment targets, expectations, and recommendations have an influence on parental targets, contributing to the differences in pediatric diabetes center outcomes.

Revisiting autoimmune gastritis in children and adolescents with type 1 diabetes.

OBJECTIVE: Assess the frequency of anti-H+ /K+ adenosine triphosphatase (ATPase) autoantibodies (AAB) and symptoms of autoimmune gastritis in children and adolescents with type 1 diabetes (T1D). RESEARCH DESIGN AND METHODS: Anti-H+ /K+ ATPase AAB were measured in 402 children and adolescents (210 boys and 192 girls, 11.1 ± 4.5 years) treated for T1D (screened positive for ß-cell AAB), along with search of symptoms of anemia (hemoglobin, serum iron, and ferritin levels) and gastric pain. The AAB specific for thyroperoxydase, thyroglobulin, and transglutaminase were also measured. RESULTS: Anti-H+ /K+ ATPase AAB were present in 6.5% of children. Their frequency increased with age: 4% at 10 years, 10% at 15 years, and 20% at 20 years. Iron deficiency (45% vs 3.8%), iron deficiency anemia (36% vs 3.8%), antithyroid AAB (24% vs 9.7%), and family history of Graves' disease (25% vs 5.6%) were more frequent in patients with anti-H+ /K+ ATPase AAB. Two patients, a 13-year-old girl and a 11-year-old boy, experienced symptoms (iron deficiency anemia and epigastric pain) which led to diagnosis of autoimmune gastritis confirmed upon fibroscopy. Both showed high levels of anti-H+ /K+ ATPase AAB and atrophic gastritis. CONCLUSIONS: Autoimmune gastritis presents an age-dependent frequency in children and adolescents with T1D but is rarely symptomatic. Screening for anti-H+ /K+ ATPase AAB should thus target patients with iron deficiency, anemia, epigastralgia, autoimmune thyroiditis, or age over 15 years.

Diabetes knowledge in adolescents with type 1 diabetes and their parents and glycemic control.

OBJECTIVE: To evaluate diabetes knowledge and skills (DKS) in adolescents (>10 year) with type 1 diabetes (T1D) and their parents, and its effect on glycemic control. METHODS: A ready-to-use program and a standardized questionnaire comprising 50 true-false questions based on this program, were elaborated by a National Committee, to help dispensing education at diagnosis of T1D. The questionnaire was completed by 2933 T1D patients (49% girls, 51% boys; 14.1 ± 2.5 year), 2180 mothers and 798 fathers, in 115 pediatric centers. Associations between DKS score (number of correct answers), glycated hemoglobin (HbA1c) and sociofamilial characteristics were assessed. RESULTS: DKS score increased with age, and was higher in girls than in boys and in mothers than in fathers; it correlated strongly between adolescents and their own parents; it was higher when adolescents had previously participated in diabetes camp and when parents had higher academic levels. HbA1c decreased significantly with parents' higher DKS score and academic level, and when both parents lived together. Mean adolescent DKS score was significantly higher in patients with HbA1c below 8% or 8.5% than for patients with HbA1c above these thresholds. CONCLUSION: A large survey in T1D children and adolescents and their parents showed associations between DKS and glycemic control, and the major role of sociofamilial factors.

Insulin regimens, diabetes knowledge, quality of life, and HbA1c in children and adolescents with type 1 diabetes.

OBJECTIVES: To further describe the changes in insulin therapy regimens and hemoglobin A1c (HbA1c) in children and adolescents with type 1 diabetes, and their associations with diabetes knowledge and quality of life. RESEARCH DESIGN AND METHODS: The study included 4293 children and adolescents (12.9 ± 2.6 yr, diabetes >1 yr) attending AJD (Aide aux Jeunes Diabétiques) summer camps between 2009 and 2014. The distribution of insulin regimens and associations between HbA1c, therapeutic regimens, diabetes knowledge (AJD questionnaire), and Quality of Life (Ingersoll et Marrero, Hvidoere Study Group short version) were assessed. RESULTS: The percentage of youth treated with insulin pumps increased up to about 45%, basal bolus stabilized around 40%, and other regimens decreased majorly. HbA1c was higher with premixed insulins only regimens (9.05 ± 2.43%), but there was no difference between pump (8.12 ± 1.09%), basal bolus (8.32 ± 1.33%) and two to three injections (8.18 ± 1.28%). Mean HbA1c decreased by 0.014% per year. The percentage of HbA1c <7.5% increased by 1.5% per year, and the percentages of HbA1c >9% or >10% decreased by 4 and 5.5%, changes being greater with the pump. HbA1c was weakly associated with diabetes knowledge, and strongly with general health perception and perception about diabetes. CONCLUSION: The percentage of children and adolescents with the highest risk of complications decreased markedly. The distribution of HbA1c better depicts the glycemic control in a population than the mean or the percentage of patients reaching the target (7.5%). HbA1c was more strongly associated with general health perception than with therapeutic regimens and diabetes knowledge.

A unique CD8(+) T lymphocyte signature in pediatric type 1 diabetes.

Human type 1 diabetes results from a destructive auto-reactive immune response in which CD8(+) T lymphocytes play a critical role. Given the intense ongoing efforts to develop immune intervention to prevent and/or cure the disease, biomarkers suitable for prediction of disease risk and progress, as well as for monitoring of immunotherapy are required. We undertook separate multi-parameter analyses of single naïve and activated/memory CD8(+) T lymphocytes from pediatric and adult patients, with the objective of identifying cellular profiles associated with onset of type 1 diabetes. We observe global perturbations in gene and protein expression and in the abundance of T cell populations characterizing pediatric but not adult patients, relative to age-matched healthy individuals. Pediatric diabetes is associated with a unique population of CD8(+) T lymphocytes co-expressing effector (perforin, granzyme B) and regulatory (transforming growth factor ß, interleukin-10 receptor) molecules. This population persists after metabolic normalization and is especially abundant in children with high titers of auto-antibodies to glutamic acid decarboxylase and with elevated HbA1c values. These findings highlight striking differences between pediatric and adult type 1 diabetes, indicate prolonged large-scale perturbations in the CD8(+) T cell compartment in the former, and suggest that CD8(+)CD45RA(-) T cells co-expressing effector and regulatory factors are of interest as biomarkers in pediatric type 1 diabetes.

Bone imaging findings in genetic and acquired lipodystrophic syndromes: an imaging study of 24 cases.

OBJECTIVE: To describe the bone imaging features of lipodystrophies in the largest cohort ever published. MATERIALS AND METHODS: We retrospectively examined bone imaging data in 24 patients with lipodystrophic syndromes. Twenty-two had genetic lipodystrophy: 12/22 familial partial lipodystrophy (FPLD) and 10/22 congenital generalized lipodystrophy (CGL), 8 with AGPAT2-linked CGL1 and 2 with seipin-linked CGL2. Two patients had acquired generalized lipodystrophy (AGL) in a context of non-specific autoimmune disorders. Skeletal radiographs were available for all patients, with radiographic follow-up for two. Four patients with CGL1 underwent MRI, and two of them also underwent CT. RESULTS: Patients with FPLD showed non-specific degenerative radiographic abnormalities. Conversely, CGL patients showed three types of specific radiographic alterations: diffuse osteosclerosis (in 7 patients, 6 with CGL1 and 1 with CGL2), well-defined osteolytic lesions sparing the axial skeleton (7 CGL1 and 1 CGL2), and pseudo-osteopoikilosis (4 CGL1). Pseudo-osteopoikilosis was the sole bone abnormality observed in one of the two patients with AGL. Osteolytic lesions showed homogeneous low signal intensity (SI) on T1-weighted and high SI on T2-weighted MR images. Most of them were asymptomatic, although one osteolytic lesion resulted in a spontaneous knee fracture and secondary osteoarthritis in a patient with CGL1. MRI also showed diffuse fatty bone marrow alterations in patients with CGL1, with intermediate T1 and high T2 SI, notably in radiographically normal areas. CONCLUSIONS: The three types of peculiar imaging bone abnormalities observed in generalized lipodystrophic syndromes (diffuse osteosclerosis, lytic lesions and/or pseudo-osteopoikilosis) may help clinicians with an early diagnosis in pauci-symptomatic patients.

GAD65 antigen therapy in recently diagnosed type 1 diabetes mellitus.

BACKGROUND: The 65-kD isoform of glutamic acid decarboxylase (GAD65) is a major autoantigen in type 1 diabetes. We hypothesized that alum-formulated GAD65 (GAD-alum) can preserve beta-cell function in patients with recent-onset type 1 diabetes. METHODS: We studied 334 patients, 10 to 20 years of age, with type 1 diabetes, fasting C-peptide levels of more than 0.3 ng per milliliter (0.1 nmol per liter), and detectable serum GAD65 autoantibodies. Within 3 months after diagnosis, patients were randomly assigned to receive one of three study treatments: four doses of GAD-alum, two doses of GAD-alum followed by two doses of placebo, or four doses of placebo. The primary outcome was the change in the stimulated serum C-peptide level (after a mixed-meal tolerance test) between the baseline visit and the 15-month visit. Secondary outcomes included the glycated hemoglobin level, mean daily insulin dose, rate of hypoglycemia, and fasting and maximum stimulated C-peptide levels. RESULTS: The stimulated C-peptide level declined to a similar degree in all study groups, and the primary outcome at 15 months did not differ significantly between the combined active-drug groups and the placebo group (P=0.10). The use of GAD-alum as compared with placebo did not affect the insulin dose, glycated hemoglobin level, or hypoglycemia rate. Adverse events were infrequent and mild in the three groups, with no significant differences. CONCLUSIONS: Treatment with GAD-alum did not significantly reduce the loss of stimulated C peptide or improve clinical outcomes over a 15-month period. (Funded by Diamyd Medical and the Swedish Child Diabetes Foundation; ClinicalTrials.gov number, NCT00723411.).

Changes in insulin therapy regimens over 10 yr in children and adolescents with type 1 diabetes attending diabetes camps.

OBJECTIVE: To describe the changes in insulin therapy regimens of children and adolescents with type 1 diabetes over 10 yr and their correlation with hemoglobin A1c (HbA1c). RESEARCH DESIGN AND METHODS: The study included 7206 children and adolescents (age 12.8 ± 2.7 yr, more than 1 yr of diabetes duration) admitted in summer camps between 1998 and 2007 (707-896/yr). Based on injection times (breakfast, lunch, afternoon, dinner, bedtime) and insulin types (short, long and premixed; human or analog), 786 different therapeutic combinations were classified in six main types of regimens. The distribution of the different regimens and their correlation with HbA1c were evaluated as a function of year and age. RESULTS: Over 10 yr, basal bolus increased from 13 to 52% and the pump from <1 to 13%, regimens with two to three injections per day decreased from 50 to 25%, those with only premixed insulins from 33 to 7%, and diverse regimens from 9 to 1%. HbA1c was significantly higher with premixed insulin only, but there were no differences between the other regimens throughout the follow-up. Mean yearly HbA1c (8.21-8.45%) did not show any significant decrease, but the percentage of patients with HbA1c > 9 and 10% decreased significantly, in those treated with two to three injections and the pump, not with basal bolus or premixed only regimens. CONCLUSION: A major trend in intensifying insulin treatment in children and adolescents with type 1 diabetes was accompanied by modest improvements in HbA1c. No insulin regimen has shown any better results, except over premixed insulins.

Recommendations for age-appropriate education of children and adolescents with diabetes and their parents in the European Union.

Education is the keystone of diabetes care, and structured self-management education is the key to a successful outcome. Existing guidelines provide comprehensive guidance on the various aspects of education and offer general and organizational principles of education, detailed curricula at different ages and stages of diabetes, and recommendations on models, methods, and tools to attain educative objectives. The International Society for Pediatric and Adolescent Diabetes guidelines give the most elaborate and detailed descriptions and recommendations on the practice of education, which other national guidelines address on specific aspects of education and care. The aim of the work package on education developed by Better Control in Paediatric and Adolescent Diabetes in the European Union: Working to Create Centers of Reference (SWEET) project was not to generate new guidelines but to evaluate how the existing guidelines were implemented in some pediatric diabetes reference centers. The SWEET members have completed a questionnaire that elaborates on the many aspects of delivery of education. This survey highlights a profound diversity of practices across centers in Europe, in terms of organization as well as the practices and the content of initial and continuing education. A toolbox is being developed within SWEET to facilitate exchanges on all aspects of education and to establish a process of validation of materials, tools, written structured age-adjusted programs, and evaluation procedures for the education of children and adolescents with diabetes.

Comorbidity and metabolic context are crucial factors determining neurological sequelae of hypoglycaemia.

AIM: To determine risk factors for neurological sequelae following hypoglycemia. METHOD: We analysed the neurological outcome in 164 patients (mean age 10y 10mo, SD 5.9) following hypoglycemia due to three diseases with various metabolic contexts, different ages at onset, and combinations with comorbidity (fever/infection, hypoxia/ischemia): glycogen storage disease type I (GSDI) (21 patients, mean age at first hypoglycemic episode 3.8mo, SD 3.5); fatty acid ß-oxidation defects (FAOD) (29 patients, mean age at first hypoglycemic episode 14.8mo, SD 12.6); and hyperinsulinism (HIns) (114 patients, mean age at first hypoglycemic episode 2.3mo, SD 4.7). RESULTS: Risk factors of poor neurological outcome were aetiology (p<0.006), comorbidity (p<0.001), and prolonged convulsions (p<0.001). Ordinal logistic regression showed that comorbidity (p<0.001) and status epilepticus (p=0.002) were the main determinants of sequelae. Asymptomatic hypoglycemia did not lead to sequelae, whatever the aetiology. Age was not correlated to sequelae, whatever the aetiology. The highest prevalence of hypoglycemic sequelae was found in FAOD and HIns combined with comorbidity, the lowest in GSDI (p<0.001) in which hypoglycemia is often asymptomatic, associated with increased plasma lactate, and rarely combined with comorbidity. INTERPRETATION: Hypoglycemia is severely deleterious for the brain in the context of fever/infection and/or hypoxia/ischemia, and status epilepticus. The metabolic context providing alternative fuels may improve neurological outcome.

Switching from insulin to oral sulfonylureas in patients with diabetes due to Kir6.2 mutations.

BACKGROUND: Heterozygous activating mutations in KCNJ11, encoding the Kir6.2 subunit of the ATP-sensitive potassium (K(ATP)) channel, cause 30 to 58 percent of cases of diabetes diagnosed in patients under six months of age. Patients present with ketoacidosis or severe hyperglycemia and are treated with insulin. Diabetes results from impaired insulin secretion caused by a failure of the beta-cell K(ATP) channel to close in response to increased intracellular ATP. Sulfonylureas close the K(ATP) channel by an ATP-independent route. METHODS: We assessed glycemic control in 49 consecutive patients with Kir6.2 mutations who received appropriate doses of sulfonylureas and, in smaller subgroups, investigated the insulin secretory responses to intravenous and oral glucose, a mixed meal, and glucagon. The response of mutant K(ATP) channels to the sulfonylurea tolbutamide was assayed in xenopus oocytes. RESULTS: A total of 44 patients (90 percent) successfully discontinued insulin after receiving sulfonylureas. The extent of the tolbutamide blockade of K(ATP) channels in vitro reflected the response seen in patients. Glycated hemoglobin levels improved in all patients who switched to sulfonylurea therapy (from 8.1 percent before treatment to 6.4 percent after 12 weeks of treatment, P<0.001). Improved glycemic control was sustained at one year. Sulfonylurea treatment increased insulin secretion, which was more highly stimulated by oral glucose or a mixed meal than by intravenous glucose. Exogenous glucagon increased insulin secretion only in the presence of sulfonylureas. CONCLUSIONS: Sulfonylurea therapy is safe in the short term for patients with diabetes caused by KCNJ11 mutations and is probably more effective than insulin therapy. This pharmacogenetic response to sulfonylureas may result from the closing of mutant K(ATP) channels, thereby increasing insulin secretion in response to incretins and glucose metabolism. (ClinicalTrials.gov number, NCT00334711 [ClinicalTrials.gov].).

Developmental methylation program and concerted expression of Stx11 in mouse tissues.

The human 6q24 region is involved in growth and development, transient neonatal diabetes (TND), cancer, and metabolic dysfunction. To further characterize this region, the developmental status of DNA methylation and expression of Zac1 and Stx11 genes located within the mouse 10A1 region ortholog of human 6q24 were determined. In mice, imprinted Zac1 and Stx11 were highly expressed at the end of fetal development but downregulated at 4 and 11 weeks in brain, pancreas, and heart. Postnatal Zac1 downregulation was independent from promoter methylation of the expressed allele, suggesting the mediation of age-dependent chromatin remodeling. Stx11 nonpromoter CpG island was methylated de novo from E18 to 1 year with tissue-specific kinetics. The high conservation in vertebrates of Stx11 CpG2 is suggestive of an important regulatory function in age-related regional epigenetic state and/or chromatin configuration. Stx11 alleles were unequally expressed in F1 mice tissues, reflecting the influence of cis-regulatory factors on its expression. These data suggest the presence of a methylation domain and a coordinated gene expression pattern in multiple tissues. Methylation variation and allelic regulation of expression may underlie genetic diversity and contribute to disease susceptibility at the 6q24 locus in humans.

Glucose tolerance and insulin secretion, morbidity, and death in patients with cystic fibrosis.

OBJECTIVES: To describe the history, mechanisms, and consequences of cystic fibrosis (CF)-related diabetes, from childhood to early adulthood. STUDY DESIGN: Pancreatic beta-cell function was estimated from the plasma insulin/glucose ratios during oral glucose tolerance test (total area under the curve and deltaI(30-0min)/G(30min), homeostasis model assessment [HOMA]%B), insulin sensitivity with the HOMA%S index, in 237 children with CF (109 boys, 128 girls). Progression of glucose metabolism abnormalities was evaluated by analysis for interval censored data; rates of pulmonary transplantation and death by Kaplan-Meier analysis. RESULTS: Impaired glucose tolerance was found in 20% of patients at 10 years, 50% at 15 years, 75% at 20 years, 82% at 30 years; for diabetes, >20% at 15 year, 45% at 20 years, 70% at 30 years; for insulin treatment, 30% at 20 years, 40% at 30 years. Early impairment was associated with lower survival rates and higher rates of lung transplantation. The area under the curve(glucose) correlated with decreased body mass index and height. Decrease in early insulin secretion (deltaI(30-0min)/G(30min)) was associated with impaired glucose tolerance, in all estimates of insulin secretion with diabetes. HOMA%S did not differ between the groups. Increased inflammation correlated with insulin resistance and impaired glucose tolerance. CONCLUSIONS: CF-related diabetes, mainly because of beta-cell deficiency, is frequent early in life and associated with impaired nutritional state and growth, increased rates of terminal respiratory failure, and death.

High Prevalence of Polycystic Ovary Syndrome in Type 1 Diabetes Mellitus Adolescents: Is There a Difference Depending on the NIH and Rotterdam Criteria?

BACKGROUND: Polycystic ovary syndrome (PCOS) is more frequently observed in type 1 diabetes mellitus (T1DM) adult women than in nondiabetic women. No such prevalence has yet been studied in adolescent girls with T1DM. AIM: The aim of this study was to evaluate the prevalence of PCOS in adolescent girls with T1DM and to determine the clinical and hormonal features associated with the disorder. METHODS: A cross-sectional study of 53 adolescent girls (gynecological age >2 years) referred for routine evaluation for T1DM was conducted. We diagnosed PCOS using the National Institutes of Health (NIH) and Rotterdam criteria. RESULTS: 26.4 and 47.9% of adolescents had PCOS according to NIH (NIH-PCOS) and Rotterdam (Rotterdam-PCOS) criteria. 66.7% of NIH-PCOS adolescents had a complete phenotype associated with hyperandrogenism, oligomenorrhea, and polycystic ovarian morphology, unlike only 33.3% of the Rotterdam-PCOS adolescents. A family history of type 2 diabetes mellitus (T2DM) was more frequent in PCOS than in non-PCOS girls, whichever criteria were used. Late pubertal development and a T1DM diagnosis close to puberty were factors associated with NIH-PCOS. CONCLUSION: Adolescents with T1DM had a high prevalence of PCOS. More differences between PCOS and non-PCOS patients were found using the NIH criteria, suggesting that clinical characteristics might be more accurate for diagnosing PCOS in girls with T1DM. A family history of T2DM is associated with a high risk of PCOS.

The Knudson's two-hit model and timing of somatic mutation may account for the phenotypic diversity of focal congenital hyperinsulinism.

BACKGROUND: Congenital hyperinsulinism (CHI) is associated with focal hyperplasia of endocrine tissue in 40-65% of patients. Focal CHI is sporadic and is caused by a germline, paternally inherited, mutation of the SUR1 (ABCC8) or KIR6.2 (KCNJ11) genes (encoding subunits of the pancreatic ATP-dependent potassium channel) together with somatic maternal haploinsufficiency for 11p15.5. Plurifocal or large forms of focal CHI are a cause of apparent failure of surgery, and their underlying mechanism has not been thoroughly investigated. PATIENTS: We here report two patients with bifocal CHI as evidenced by relapsing hypoglycemia after removal of the first focal lesion and the detection of a second, distinct, focal adenomatous hyperplasia during later surgery (patients 1 and 2) and a patient with a giant focal lesion involving the major part of the pancreas (patient 3). RESULTS: In the three patients, a germline, paternally inherited, mutation of SUR1 was found. In patients 1 and 2, haploinsufficiency for the maternal 11p15.5 region resulted from a somatic deletion specific for each of the focal lesions, as shown by the diversity of deletion break points. In patient 3, an identical somatic maternal 11p15 deletion demonstrated by similar break points was shown in two independent lesion samples, suggesting a very early event during pancreas embryogenesis. CONCLUSION: Individual patients with focal hyperinsulinism may have more than one focal pancreatic lesion due to separate somatic maternal deletion of the 11p15 region. These patients and those with solitary focal lesions may follow the two-hit model described by Knudson. The stage of embryogenesis at which the somatic event occurs may account for the observed histological diversity (early event giant lesion, later event small lesion).

Congenital hyperinsulinism: pancreatic [18F]fluoro-L-dihydroxyphenylalanine (DOPA) positron emission tomography and immunohistochemistry study of DOPA decarboxylase and insulin secretion.

CONTEXT: Congenital hyperinsulinism (HI) is characterized by hypoglycemia related to inappropriate insulin secretion. Focal and diffuse forms of hyperinsulinism share a similar clinical presentation, but their treatment is dramatically different. Preoperative differential diagnosis was based on pancreatic venous sampling, a technically demanding technique. OBJECTIVE: Positron emission tomography (PET) after injection of [18F]fluoro-L-DOPA (L-dihydroxyphenylalanine) has been evaluated for the preoperative differentiation between focal and diffuse HI, by imaging uptake of radiotracer and the conversion of [18F]fluoro-L-dopa into dopamine by DOPA decarboxylase. We propose to validate this test by immunohistochemical approach. PATIENTS AND METHODS: Pancreatic surgical specimens of four focal and three diffuse HI were studied, using anti-DOPA decarboxylase and proinsulin antibodies. The effect of an inhibitor of DOPA decarboxylase (carbidopa) on insulin secretion was evaluated in vivo and in cultured INS-1 cells. RESULTS: Immunohistochemical detection of DOPA decarboxylase showed diffuse staining of Langerhans islets in the whole pancreas in all diffuse cases, in contrast with dense focal staining in all focal cases. Staining of Langerhans islets outside the focal lesion was diffusely but weakly positive. We correlated the localization of DOPA decarboxylase and proinsulin in normal pancreas and in both diffuse and focal HI tissues. The diffuse PET uptake found before treatment in one child with diffuse HI disappeared completely after carbidopa administration, suggesting in vivo that pancreatic cells can take up amine precursors and contain DOPA decarboxylase. The insulin secretion measured in the supernatant was the same whether INS-1 cells were treated by dopamine or Lodosyn or untreated. CONCLUSION: We validate PET with as a consistent test to differentiate diffuse and focal HI.

KCNJ11 activating mutations are associated with developmental delay, epilepsy and neonatal diabetes syndrome and other neurological features.

Heterozygous activating mutations in the gene encoding for the ATP-sensitive potassium channel subunit Kir6.2 (KCNJ11) have recently been shown to be a common cause of permanent neonatal diabetes. Kir6.2 is expressed in muscle, neuron and brain as well as the pancreatic beta-cell, so patients with KCNJ11 mutations could have a neurological phenotype in addition to their diabetes. It is proposed that some patients with KCNJ11 mutations have neurological features that are part of a discrete neurological syndrome termed developmental Delay, Epilepsy and Neonatal Diabetes (DEND), but there are also neurological consequences of chronic or acute diabetes. We identified KCNJ11 mutations in four of 10 probands with permanent neonatal diabetes and one affected parent; this included the novel C166F mutation and the previously described V59M and R201H. Four of the five patients with mutations had neurological features: the patient with the C166F mutation had marked developmental delay, severe generalised epilepsy, hypotonia and muscle weakness; mild developmental delay was present in the patient with the V59M mutation; one patient with the R201H mutation had acute and chronic neurological consequences of cerebral oedema and another had diabetic neuropathy from chronic hyperglycaemia. In conclusion, the clinical features in these patients support the existence of a discrete neurological syndrome with KCNJ11 mutations. The severe DEND syndrome was seen with the novel C166F mutation and mild developmental delay with the V59M mutation. These features differ markedly from the neurological consequences of acute or chronic diabetes.

Prevalence of mutations in AGPAT2 among human lipodystrophies.

Berardinelli-Seip congenital lipodystrophy (BSCL) is a heterogeneous genetic disease characterized by near absence of adipose tissue and severe insulin resistance. We have previously identified mutations in the seipin gene in a subset of our patients' cohort. Recently, disease-causing mutations in AGPAT2 have been reported in BSCL patients. In this study, we have performed mutation screening in AGPAT2 and the related AGPAT1 in patients with BSCL or other forms of lipodystrophy who have no detectable mutation in the seipin gene. We found 38 BSCL patients from 30 families with mutations in AGPAT2. Three of the known mutations were frequently found in our families. Of the eight new alterations, six are null mutations and two are missense mutations (Glu172Lys and Ala238Gly). All the patients harboring AGPAT2 mutations presented with typical features of BSCL. We did not find mutations in patients with other forms of lipodystrophies, including the syndromes of Lawrence, Dunnigan, and Barraquer-Simons, or with type A insulin resistance. In conclusion, mutations in the seipin gene and AGPAT2 are confined to the BSCL phenotype. Because we found mutations in 92 of the 94 BSCL patients studied, the seipin gene and AGPAT2 are the two major genes involved in the etiology of BSCL.

Wolcott-Rallison Syndrome: clinical, genetic, and functional study of EIF2AK3 mutations and suggestion of genetic heterogeneity.

Wolcott-Rallison syndrome (WRS) is a rare autosomal-recessive disorder characterized by the association of permanent neonatal or early-infancy insulin-dependent diabetes, multiple epiphyseal dysplasia and growth retardation, and other variable multisystemic clinical manifestations. Based on genetic studies of two inbred families, we previously identified the gene responsible for this disorder as EIF2AK3, the pancreatic eukaryotic initiation factor 2alpha (eIF2alpha) kinase. Here, we have studied 12 families with WRS, totalling 18 cases. With the exception of one case, all patients carried EIF2AK3 mutations resulting in truncated or missense versions of the protein. Exclusion of EIF2AK3 mutations in the one patient case was confirmed by both linkage and sequence data. The activities of missense versions of EIF2AK3 were characterized in vivo and in vitro and found to have a complete lack of activity in four mutant proteins and residual kinase activity in one. Remarkably, the onset of diabetes was relatively late (30 months) in the patient expressing the partially defective EIF2AK3 mutant and in the patient with no EIF2AK3 involvement (18 months) compared with other patients (<6 months). The patient with no EIF2AK3 involvement did not have any of the other variable clinical manifestations associated with WRS, which supports the idea that the genetic heterogeneity between this variant form of WRS and EIF2AK3 WRS correlates with some clinical heterogeneity.