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Aim In the pediatric diabetes clinic, patients with type 1 diabetes mellitus (T1D) account for more than 90% of cases, while monogenic forms represent about 6%. Many monogenic diabetes subtypes may respond to therapies other than insulin and have chronic diabetes complication prognosis that is different from T1D. With the aim of providing a better diagnostic pipeline and a tailored care for patients with monogenic diabetes, we set up a monogenic diabetes clinic (MDC). Methods In the first 3 years of activity 97 patients with non-autoimmune forms of hyperglycemia were referred to MDC. Genetic testing was requested for 80 patients and 68 genetic reports were available for review. Results In 58 subjects hyperglycemia was discovered beyond 1 year of age (Group 1) and in 10 before 1 year of age (Group 2). Genetic variants considered causative of hyperglycemia were identified in 25 and 6 patients of Group 1 and 2, respectively, with a pick up rate of 43.1% (25/58) for Group 1 and 60% (6/10) for Group 2 (global pick-up rate: 45.5%; 31/68). When we considered probands of Group 1 with a parental history of hyperglycemia, 58.3% (21/36) had a positive genetic test for GCK or HNF1A genes, while pick-up rate was 18.1% (4/22) in patients with mute family history for diabetes. Specific treatments for each condition were administered in most cases. Conclusion We conclude that MDC maycontribute to provide a better diabetes care in the pediatric setting.

Background/Aims: Mutations in KCNJ11, the gene encoding the Kir6.2 subunit of pancreatic and neuronal KATP channels, are associated with a spectrum of neonatal diabetes diseases. Methods: Variant screening was used to identify the cause of neonatal diabetes, and continuous glucose monitoring was used to assess effectiveness of sulfonylurea treatment. Electrophysiological analysis of variant KATP channel function was used to determine molecular basis. Results: We identified a previously uncharacterized KCNJ11 mutation, c.988T>C [p.Tyr330His], in an Italian child diagnosed with sulfonylurea-resistant permanent neonatal diabetes and developmental delay (intermediate DEND). Functional analysis of recombinant KATP channels reveals that this mutation causes a drastic gain-of-function, due to a reduction in ATP inhibition. Further, we demonstrate that the Tyr330His substitution causes a significant decrease in sensitivity to the sulfonylurea, glibenclamide. Conclusions: In this subject, the KCNJ11 (c.988T>C) mutation provoked neonatal diabetes, with mild developmental delay, which was insensitive to correction by sulfonylurea therapy. This is explained by the molecular loss of sulfonylurea sensitivity conferred by the Tyr330His substitution and highlights the need for molecular analysis of such mutations.

OBJECTIVE ABCC8 mutations cause neonatal diabetes mellitus that can be transient (TNDM) or, less commonly, permanent (PNDM); ∼90% of individuals can be treated with oral sulfonylureas instead of insulin. Previous studies suggested that people with ABCC8-PNDM require lower sulfonylurea doses and have milder neurological features than those with KCNJ11-PNDM. However, these studies were short-term and included combinations of ABCC8-PNDM and ABCC8-TNDM. We aimed to assess the long-term glycemic and neurological outcomes in sulfonylurea-treated ABCC8-PNDM. RESEARCH DESIGN AND METHODS We studied all 24 individuals with ABCC8-PNDM diagnosed in the U.K., Italy, France, and U.S. known to transfer from insulin to sulfonylureas before May 2010. Data on glycemic control, sulfonylurea dose, adverse effects including hypoglycemia, and neurological features were analyzed using nonparametric statistical methods. RESULTS Long-term data were obtained for 21 of 24 individuals (median follow-up 10.0 [range 4.1–13.2] years). Eighteen of 21 remained on sulfonylureas without insulin at the most recent follow-up. Glycemic control improved on sulfonylureas (presulfonylurea vs. 1-year posttransfer HbA1c 7.2% vs. 5.7%, P = 0.0004) and remained excellent long-term (1-year vs. 10-year HbA1c 5.7% vs. 6.5%, P = 0.04), n = 16. Relatively high doses were used (1-year vs. 10-year dose 0.37 vs. 0.25 mg/kg/day glyburide, P = 0.50) without any severe hypoglycemia. Neurological features were reported in 13 of 21 individuals; these improved following sulfonylurea transfer in 7 of 13. The most common features were learning difficulties (52%), developmental delay (48%), and attention deficit hyperactivity disorder (38%). CONCLUSIONS Sulfonylurea treatment of ABCC8-PNDM results in excellent long-term glycemic control. Overt neurological features frequently occur and may improve with sulfonylureas, supporting early, rapid genetic testing to guide appropriate treatment and neurodevelopmental assessment.

Insulin-resistant diabetes in Rabson–Mendenhall syndrome (RMS) is relatively unresponsive to first-line antidiabetic treatments, including metformin and insulin. We report 2 patients with RMS treated with 2 different sodium-glucose cotransporter inhibitors 2: empagliflozin in an 11-year-old boy and dapagliflozin in a 12-year-old girl. In the first patient, we began empagliflozin at 2.5 mg/day and increased the dose to 10 mg/day over 3 months. During treatment with empagliflozin, the amount of time during which the patient maintained serum glucose in the 70 to 180 mg/dL target range increased by 2 hours per day. Hemoglobin A1C dropped from >14% to 11.9%, urinary calcium increased almost twofold, and β-hydroxybutyrate remained 50%. In 2 patients with RMS, empagliflozin and dapagliflozin were well tolerated and improved glycemic control without significantly increasing ketonemia. Renal calcium excretion should be carefully monitored.

Monogenic diabetes, a form of diabetes mellitus, is caused by a mutation in a single gene and may account for 1-2% of all clinical forms of diabetes. To date, more than 40 loci have been associated with either isolated or syndromic monogenic diabetes.While the request of a genetic test is mandatory for cases with diabetes onset in the first 6 months of life, a decision may be difficult for childhood or adolescent diabetes. In an effort to assist the clinician in this task, we have grouped monogenic diabetes genes according to the age of onset (or incidental discovery) of hyperglycemia and described the additional clinical features found in syndromic diabetes. The therapeutic options available are reviewed.Technical improvements in DNA sequencing allow for rapid, simultaneous analysis of all genes involved in monogenic diabetes, progressively shrinking the area of unsolved cases. However, the complexity of the analysis of genetic data requires close cooperation between the geneticist and the diabetologist, who should play a proactive role by providing a detailed clinical phenotype that might match a specific disease gene.

Limitations in cell proliferation are important for normal function of differentiated tissues and essential for the safety of cell replacement products made from pluripotent stem cells, which have unlimited proliferative potential. To evaluate whether these limitations can be established pharmacologically, we exposed pancreatic progenitors differentiating from human pluripotent stem cells to small molecules that interfere with cell cycle progression either by inducing G1 arrest or by impairing S phase entry or S phase completion and determined growth potential, differentiation, and function of insulin-producing endocrine cells. We found that the combination of G1 arrest with a compromised ability to complete DNA replication promoted the differentiation of pancreatic progenitor cells toward insulin-producing cells and could substitute for endocrine differentiation factors. Reduced replication fork speed during differentiation improved the stability of insulin expression, and the resulting cells protected mice from diabetes without the formation of cystic growths. The proliferative potential of grafts was proportional to the reduction of replication fork speed during pancreatic differentiation. Therefore, a compromised ability to enter and complete S phase is a functionally important property of pancreatic endocrine differentiation, can be achieved by reducing replication fork speed, and is an important determinant of cell-intrinsic limitations of growth.

Background: When very low doses of insulin are used insulin dilution, a procedure prone to errors, is recommended.Case presentation: We managed a neonate with pancreas agenesis with insulin pump therapy from the first days of life to 16 months of age without insulin dilution. Predictive low glucose suspend mode first and then closed loop control were used. No episodes of severe hypoglycemia were observed. Conclusions: Though limited to a single patient with pancreas agenesis we believe that the use of pump should be warranted in patients with permanent neonatal diabetes mellitus and intestinal malabsorp-tion, even with undiluted insulin.(c) 2022 Diabetes India. Published by Elsevier Ltd. All rights reserved.

iNtrOdUctiON: type 2 diabetes (t2d) in adolescents has become an increasing health concern throughout the world and its prevention and screening should be implemented in pediatric care. as clinical features at presentation, in some cases can be similar to type 1 diabetes and family history can be in favor of a monogenic form of diabetes, it is pivotal for physicians to be aware of youth-onset T2D specificities to ensure an accurate diagnosis. EVIDENCE ACQUISITION: We conducted the first search in Medline, Embase, Web of Science, using different keywords and their compositions. The keywords used, also called “mesh” (MEdical Subject Headings) on PubMed, are the following: “type 2 diabetes” AND (“child*” OR “pediatr*” OR “adolesce*”) AND (“epidem*” OR “diagnos*” OR “treat*” OR “complication” OR “comorbidit*”). International review, systematic reviews and meta-analyses, randomized control trials and case reports published between May 2018 and February 2021 were considered, to identify publications that deal with the topic. No restrictions were applied regarding the published paper’s language. eVideNce sYNtHesis: the global increase of overweight and obesity can complicate the diagnostic process and makes it essential to apply a systematic approach to each new diagnosis. Microvascular complications may be present at the time of diagnosis and chronic complications are frequent and need to be screened regularly. regular screening of comorbidities should also be performed. childhood t2d should be followed up by pediatric diabetes units to avoid diagnostic errors and delay in care. cONcLUsiONs: a multidisciplinary approach, by an experienced team, is pivotal to provide treatment options targeting the unique needs of pediatric patients. treatment programs must include the whole family and address all the aspects of the care (lifestyle, pharmacological therapy, psychological aspects, complications and comorbidities). an organized process of transition to adult care is essential.

Objective Transient neonatal diabetes mellitus (TNDM) is caused by activating mutations in ABCC8 and KCNJ11 genes (KATP/TNDM) or by chromosome 6q24 abnormalities (6q24/TNDM). We wanted to assess whether these different genetic aetiologies result in distinct clinical features. Design Retrospective analysis of the Italian data set of patients with TNDM. Methods Clinical features and treatment of 22 KATP/TNDM patients and 12 6q24/TNDM patients were compared. Results Fourteen KATP/TNDM probands had a carrier parent with abnormal glucose values, four patients with 6q24 showed macroglossia and/or umbilical hernia. Median age at diabetes onset and birth weight were lower in patients with 6q24 (1 week; −2.27 SD) than those with KATP mutations (4.0 weeks; −1.04 SD) (P = 0.009 and P = 0.007, respectively). Median time to remission was longer in KATP/TNDM than 6q24/TNDM (21.5 weeks vs 12 weeks) (P = 0.002). Two KATP/TNDM patients entered diabetes remission without pharmacological therapy. A proband with the ABCC8/L225P variant previously associated with permanent neonatal diabetes entered 7-year long remission after 1 year of sulfonylurea therapy. Seven diabetic individuals with KATP mutations were successfully treated with sulfonylurea monotherapy; four cases with relapsing 6q24/TNDM were treated with insulin, metformin or combination therapy. Conclusions If TNDM is suspected, KATP genes should be analyzed first with the exception of patients with macroglossia and/or umbilical hernia. Remission of diabetes without pharmacological therapy should not preclude genetic analysis. Early treatment with sulfonylurea may induce long-lasting remission of diabetes in patients with KATP mutations associated with PNDM. Adult patients carrying KATP/TNDM mutations respond favourably to sulfonylurea monotherapy.

Objective ABCC8 mutations cause neonatal diabetes that can be transient (TNDM) or less commonly permanent (PNDM); ~90% individuals can be treated with oral sulfonylureas instead of insulin. Previous studies suggested that people with ABCC8-PNDM require lower sulfonylurea doses and have milder neurological features than those with KCNJ11-PNDM. However, these studies were short-term and included combinations of permanent and transient forms of ABCC8-NDM. We aimed to assess the long-term glycemic and neurological outcomes in sulfonylurea-treated ABCC8-PNDM. Research Design and Methods We studied all 24 individuals with ABCC8-PNDM diagnosed in the UK, Italy, France or USA known to transfer from insulin to sulfonylureas before May 2010. Data on glycemic control, sulfonylurea dose, adverse effects including hypoglycemia, and neurological features were analysed using non-parametric statistical methods. Results Long-term data were obtained for 21/24 individuals (median follow-up 10.0 (4.1-13.2) years). 18/21 remained on sulfonylureas without insulin at most recent follow-up. Glycemic control improved on sulfonylureas (pre-sulfonylurea vs 1-year post-transfer HbA1c 7.2% vs 5.7%, p=0.0004) and remained excellent long-term (1-year vs. 10-year HbA1c 5.7% vs. 6.5%, p=0.04), n=16. Relatively high doses were used (1-year vs 10-year dose 0.37 vs 0.25mg/kg/day glyburide, p=0.50), without any severe hypoglycemia. Neurological features were reported in 13/21 individuals: these improved following sulfonylurea transfer in 7/13. The commonest features were learning difficulties (52%), developmental delay (48%), and ADHD (38%). Conclusions Sulfonylurea treatment of ABCC8-PNDM results in excellent long-term glycemic control. Overt neurological features frequently occur and may improve with sulfonylureas, supporting early, rapid genetic testing to guide appropriate treatment and neurodevelopmental assessment.

Introduction Management of Type 1 Diabetes (T1D) poses numerous challenges, especially for young children and their families. Parental care positively influences the outcomes of children with T1D, while there are often criticisms in school environment. The COVID-19 pandemic has forced children and parents to spend many hours at home and diabetes care has returned mainly in the hands of parents. Aim of the study To evaluate the effectiveness of exclusive return to parental care in pre-school and school children with T1D treated with Tandem Basal IQ system during the COVID-19 pandemic. Patients and methods 22 children (M:F = 14:8) with T1D have been evaluated. We compared insulin and CGM data (TIR, TBR and TAR) of two periods: PRE-COV and IN-COV, in which children have transitioned from normal school attendance to the exclusive care of their parents. Results During the IN-COV period a significantly (p < 0.001) higher median value of TIR (66,41%) was observed as compared to PRE-COV period (61,45%). Patients also showed a statistically significant difference (p < 0.002) between the IN-COV period and the PRE-COV period as concerning the TAR metric: respectively 29,86 ± 10,6 % vs 34,73 ± 12,8 %. The difference between the bolus insulin doses was statistically significant (PRE-COV 5,3 IU/day, IN-COV 7,9 IU/day – p

OBJECTIVE: ABCC8 mutations cause neonatal diabetes that can be transient (TNDM) or less commonly permanent (PNDM); ~90% individuals can be treated with oral sulfonylureas instead of insulin. Previous studies suggested that people with ABCC8-PNDM require lower sulfonylurea doses and have milder neurological features than those with KCNJ11-PNDM. However, these studies were short-term and included combinations of permanent and transient forms of ABCC8-NDM. We aimed to assess the long-term glycemic and neurological outcomes in sulfonylurea-treated ABCC8-PNDM. RESEARCH DESIGN AND METHODS: We studied all 24 individuals with ABCC8-PNDM diagnosed in the UK, Italy, France or USA known to transfer from insulin to sulfonylureas before May 2010. Data on glycemic control, sulfonylurea dose, adverse effects including hypoglycemia, and neurological features were analysed using non-parametric statistical methods. RESULTS: Long-term data were obtained for 21/24 individuals (median follow-up 10.0 (4.1-13.2) years). 18/21 remained on sulfonylureas without insulin at most recent follow-up. Glycemic control improved on sulfonylureas (pre-sulfonylurea vs 1-year post-transfer HbA1c 7.2% vs 5.7%, p=0.0004) and remained excellent long-term (1-year vs. 10-year HbA1c 5.7% vs. 6.5%, p=0.04), n=16. Relatively high doses were used (1-year vs 10-year dose 0.37 vs 0.25mg/kg/day glyburide, p=0.50), without any severe hypoglycemia. Neurological features were reported in 13/21 individuals: these improved following sulfonylurea transfer in 7/13. The commonest features were learning difficulties (52%), developmental delay (48%), and ADHD (38%). CONCLUSIONS: Sulfonylurea treatment of ABCC8-PNDM results in excellent long-term glycemic control. Overt neurological features frequently occur and may improve with sulfonylureas, supporting early, rapid genetic testing to guide appropriate treatment and neurodevelopmental assessment.

Transient neonatal diabetes mellitus (TNDM) is a subtype of neonatal diabetes (diagnosis: ≤ 180 days of life) characterized by remission within months from onset. TNDM is almost invariably associated with mutations in genes encoding the two subunits of ATP-dependent potassium channel (KATP), ABCC8 and KCNJ11, or with defects in chromosome 6. We reviewed genetic data, family history and clinical features including age at diabetes onset, mode of diabetes presentation, birth weight, type of diabetes treatment, time to remission, and diabetes therapy at relapse in 23 patients with TNDM of the Italian collection. Italian data set of TNDM patients included 8 cases with ABCC8 mutation, 8 cases with KCNJ11 mutation and 7 patients with 6q24 defects. Ten patients with KATP/TNDM (62%) had a parent with diabetes or IFG/IGT who carried the mutation. In contrast, none of the parents of patients with 6q24/TNDM showed glucose derangement. Age at diabetes onset did not exceed 5 weeks from birth in patients with 6q24 defects, and ranged from 1 to 34 weeks in patients with KATP mutations. Seven patients with KATP/TNDM presented with diabetic ketoacidosis (DKA); in contrast, three other patients entered into remission without any pharmacological treatment. No patients with 6q24/TNDM had DKA. Age at remission was higher for probands with KATP/TNDM than those with 6q24/TNDM (median 28.5 vs. 8 weeks, respectively, p=0.0023), along with time to remission (20.5 vs. 6 weeks, p=0.0056). Four patients with TNDM who had relapse of diabetes were treated with sulfonylureas (SU), and one with insulin (refusal of SU). Conclusions: TNDM patients with positive family history for diabetes, onset of diabetes beyond 6 weeks from birth and long time to remission should be screened for mutations in KATP genes first. Remission without therapy observed in 3 cases with KATP/TNDM suggests that in parents with diabetes onset in adolescence, mild TNDM could have been overlooked. Disclosure F. Barbetti: Consultant; Self; Amring. R. Bonfanti: Advisory Panel; Self; Abbott, Medtronic, Roche Diabetes Care. I. Rabbone: None. P. Reinstadler: None. C. Bizzarri: None. D. Iafusco: None.

Genetic testing for monogenic diabetes, essential for accurate diagnosis and appropriate treatment is underutilized. Obstacles include clinical overlap with type 1 and type 2 diabetes and difficulty distinguishing clinically significant (pathogenic/likely pathogenic; P/LP) from normal (benign/likely benign; B/LB) variation. The ClinGen Monogenic Diabetes Expert Panel (MDEP) was formed to adapt American College of Medical Genetics and Genomics/Association for Molecular Pathology (ACMG/AMP) variant interpretation guidelines to monogenic diabetes genes and enable depositing of expert panel variant reviews into ClinVar, a public database relating gene variants to phenotypes. MDEP includes endocrinologists, laboratory directors, genetic counselors, medical geneticists, clinical scientists and researchers from 37 academic and commercial institutions, allowing the panel to benefit from multiple expert perspectives and pooling of case-level data. Currently, MDEP is focusing on the three most commonly implicated monogenic diabetes genes: GCK, HNF1A and HNF4A. MDEP generated gene-specific modifications and/or strength adjustments to existing rules to provide guidance for the use of evidence, including molecular, phenotypic, segregation, functional, and minor allele frequency data. Our guidelines have so far been tested on 98 HNF1A variants, 15 HNF4A variants and 22 GCK variants selected from ClinVar and the literature. Fourteen of 31 variants of uncertain significance (VUS) in ClinVar were re-classified: nine to P/LP (enabling diagnosis and treatment) and five to B/LB (reducing ambiguity). Six LP variants and one LB variant from ClinVar were re-classified to VUS (stimulating further surveillance). MDEP’s work will improve accuracy, standardization and concordance of variant interpretation for monogenic diabetes and support wider implementation of precision medicine in diabetes. Disclosure H. Zhang: None. K.A. Maloney: None. F. Barbetti: Consultant; Self; Amring. S.W. Greeley: None. J.L.T. Kettunen: None. J.P. Miranda: None. U.L. Mirshahi: None. J. Molnes: None. R. Murphy: None. R.N. Naylor: None. R.E. Pakyz: None. L.H. Philipson: None. S. Prudente: None. T. Tuomi: None. M. Udler: None. K. Colclough: None. L. Jeng: None. T.I. Pollin: None. Funding National Institutes of Health (5U24HD093486, R01DK104942, P30DK020595 )

Summary Permanent neonatal diabetes mellitus (PNDM) can be caused by insulin mutations. We generated induced pluripotent stem cells from fibroblasts of a patient with PNDM and undetectable insulin at birth due to a homozygous mutation in the translation start site of the insulin gene. Differentiation of mutant cells resulted in insulin-negative endocrine stem cells expressing MAFA, NKX6.1, and chromogranin A. Correction of the mutation in stem cells and differentiation to pancreatic endocrine cells restored insulin production and insulin secretion to levels comparable to those of wild-type cells. Grafting of corrected cells into mice, followed by ablating mouse β cells using streptozotocin, resulted in normal glucose homeostasis, including at night, and the stem cell-derived grafts adapted insulin secretion to metabolic changes. Our study provides proof of principle for the generation of genetically corrected cells autologous to a patient with non-autoimmune insulin-dependent diabetes. These cases should be readily amenable to autologous cell therapy., Highlights • Neonatal diabetes due to homozygous mutation in the start codon of the insulin gene • iPSCs with INSATG>ATA mutation give rise to hormone-negative endocrine cells • Gene correction restores insulin production • Insulin-producing cells protect mice from diabetes, Stem cells from a subject with diabetes due to a mutation in the insulin locus can be corrected and insulin secretion restored. Grafted cells protect a mouse model from diabetes. This is a proof of principle for cell replacement for an insulin-dependent form of diabetes. Due to absence of autoimmunity such cases may be suitable for autologous cell therapy.

Diabetes mellitus and impaired fasting glucose associated with single gene mutations are less rare than previously thought and may account for more than 6% of patients attending a pediatric diabetes clinic. The number of loci involved in monogenic diabetes exceed 25, and appropriate genetic diagnosis is crucial to direct therapy, for genetic counseling and for prognosis of short- and long-term complications. Among patients with neonatal diabetes (i.e. with onset within first 6 months of life) and patients with Maturity Onset Diabetes of the Young (MODY; an autosomal dominant form of diabetes), those carrying mutations in KCNJ11, ABCC8, HNF1A and HNF4A genes usually respond to oral therapy with sulphonylurea, while those bearing GCK mutations do not necessitate any treatment. Sensor-augmented continuous subcutaneous insulin infusion has been successfully employed in neonatal diabetes, and long-lasting effectiveness of sulfonylurea in KCNJ11 mutation carriers with neonatal diabetes well documented.

Aim Hypoglycemia in childhood is very rare and can be caused by genetic mutations or insulin-secreting neoplasms. Postprandial hypoglycemia has previously been associated with insulin receptor (INSR) gene mutations. We aimed to identify the cause of postprandial hypoglycemia in a 10-year-old boy. Subjects We studied the symptomatic proband and his apparently asymptomatic mother and elder brother. All of them were lean. Methods Metabolic screening of the proband included a 5-hour oral glucose tolerance test (OGTT), angio-magnetic resonance imaging, and 18 F-dihydroxyphenylalanine positron emission tomography/computed tomography imaging of the pancreas. INSR gene sequencing and in vitro functional studies of a novel INSR mutation were also undertaken. Results Fasting hyperinsulinemia was detected during metabolic screening, and 5-hour OGTT showed hypoglycemia at 240' in the proband, his mother, and brother. Pancreatic imaging showed no evidence of neoplasia. Acanthosis nigricans with high fasting insulin levels in the proband suggested severe insulin resistance and prompted INSR gene sequencing, which revealed the novel, heterozygous p.Phe1213Leu mutation in the patient and his family members. In vitro studies showed that this mutation severely impairs insulin receptor function by abolishing tyrosine kinase activity and downstream insulin signaling. Conclusions The identification of etiological cause of hypoglycemia in childhood may be challenging. The combination of fasting hyperinsulinemia with acanthosis nigricans in a lean subject with hypoglycemia suggests severe insulin resistance and warrants INSR gene screening.

BACKGROUND: In the Joslin Medalist Study (Medalists), we determined whether significant associations exist between β cell function and pathology and clinical characteristics. METHODS: Individuals with type 1 diabetes (T1D) for 50 or more years underwent evaluation including HLA analysis, basal and longitudinal autoantibody (AAb) status, and β cell function by a mixed-meal tolerance test (MMTT) and a hyperglycemia/arginine clamp procedure. Postmortem analysis of pancreases from 68 Medalists was performed. Monogenic diabetes genes were screened for the entire cohort. RESULTS: Of the 1019 Medalists, 32.4% retained detectable C-peptide levels (>0.05 ng/mL, median: 0.21 ng/mL). In those who underwent a MMTT (n = 516), 5.8% responded with a doubling of baseline C-peptide levels. Longitudinally (n = 181, median: 4 years), C-peptide levels increased in 12.2% (n = 22) and decreased in 37% (n = 67) of the Medalists. Among those with repeated MMTTs, 5.4% (3 of 56) and 16.1% (9 of 56) had waxing and waning responses, respectively. Thirty Medalists with baseline C-peptide levels of 0.1 ng/mL or higher underwent the clamp procedure, with HLA(–)/AAb(–) and HLA(+)/AAb(–) Medalists being most responsive. Postmortem examination of pancreases from 68 Medalists showed that all had scattered insulin-positive cells; 59 additionally had few insulin-positive cells within a few islets; and 14 additionally had lobes with multiple islets with numerous insulin-positive cells. Genetic analysis revealed that 280 Medalists (27.5%) had monogenic diabetes variants; in 80 (7.9%) of these Medalists, the variants were classified as “likely pathogenic” (rare exome variant ensemble learner [REVEL] >0.75). CONCLUSION: All Medalists retained insulin-positive β cells, with many responding to metabolic stimuli even after 50 years of T1D. The Medalists were heterogeneous with respect to β cell function, and many with HLA(+) diabetes risk alleles also had monogenic diabetes variants, indicating the importance of genetic testing for clinically diagnosed T1D. FUNDING: Funding for this work was provided by the Dianne Nunnally Hoppes Fund; the Beatson Pledge Fund; the NIH, National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK); and the American Diabetes Association (ADA).

Context An etiologic diagnosis of diabetes can affect the therapeutic strategy and prognosis of chronic complications. Objective The aim of the present study was to establish the relative percentage of different diabetes subtypes in patients attending Italian pediatric diabetes centers and the influence of an etiologic diagnosis on therapy. Design, setting, and patients This was a retrospective study. The clinical records of 3781 consecutive patients (age, 0 to 18 years) referred to 15 pediatric diabetes clinics with a diagnosis of diabetes or impaired fasting glucose from January 1, 2007 to December 31, 2012 were examined. The clinical characteristics of the patients at their first referral to the centers, type 1 diabetes-related autoantibodies, molecular genetics records, and C-peptide measurements, if requested for the etiologic diagnosis, were acquired. Main outcome measures The primary outcome was to assess the percentage of each diabetes subtype in our sample. Results Type 1 diabetes represented the main cause (92.4%) of diabetes in this group of patients, followed by monogenic diabetes, which accounted for 6.3% of cases [maturity onset diabetes of the young (MODY), 5.5%; neonatal diabetes mellitus, 0.6%, genetic syndromes, 0.2%]. A genetic diagnosis prompted the transfer from insulin to sulphonylureas in 12 patients bearing mutations in the HNF1A or KCNJ11 genes. Type 2 diabetes was diagnosed in 1% of the patients. Conclusions Monogenic diabetes is highly prevalent in patients referred to Italian pediatric diabetes centers. A genetic diagnosis guided the therapeutic decisions, allowed the formulation of a prognosis regarding chronic diabetic complications for a relevant number of patients (i.e.,GCK/MODY), and helped to provide genetic counseling.

Congenital diabetes mellitus is a rare disorder characterized by hyperglycemia that occurs shortly after birth. We define "Diabetes of Infancy" if hyperglycemia onset before 6 months of life. From the clinical point of view, we distinguish two main types of diabetes of infancy: transient (TNDM), which remits spontaneously, and permanent (PNDM), which requires lifelong treatment. TNDM may relapse later in life. About 50% of cases are transient (TNDM) and 50% permanent. Clinical manifestations include severe intrauterine growth retardation, hyperglycemia and dehydration. A wide range of different associated clinical signs including facial dysmorphism, deafness and neurological, cardiac, kidney or urinary tract anomalies are reported. Developmental delay and learning difficulties may also be observed. In this paper we review all the causes of congenital diabetes and all genes and syndromes involved in this pathology. The discovery of the pathogenesis of most forms of congenital diabetes has made it possible to adapt the therapy to the diagnosis and in the forms of alteration of the potassium channels of the pancreatic Beta cells the switch from insulin to glibenclamide per os has greatly improved the quality of life. Congenital diabetes, although it is a very rare form, has been at the must of research in recent years especially for pathogenesis and pharmacogenetics. The most striking difference compared to the more frequent autoimmune diabetes in children (type 1 diabetes) is the possibility of treatment with hypoglycemic agents and the apparent lower frequency of chronic complications.

Obesity epidemic in childhood/adolescence may influence the mode of presentation of diabetes in conditions usually diagnosed in lean people like T1DM and MODY. The aim of our study was to identify clinical parameters useful for distinguishing betweeen obese patients with T1DM (T1DMob) and patients with T2DM with onset in adolescence (T2DMad). For this study, overweight/obesity was defined as BMI ≥ 95th centile for age and sex according to BMI calculator for child and teen of CDC. We compared 60 T1DMob patients (at least one T1DM autoab with high titer) with 36 patients with T2DMad (negative to T1DM autoabs). Patients with T2DMad and a parent with diabetes were considered as possibly being MODY, and excluded. We evaluated sex, ethnicity, birth weight, and age, plasma glucose, HbA1c, C-peptide, Cholesterol, HDL/Cholest., triglycerides (TG), and blood pressure (BP) at diabetes onset. Mean age at diagnosis was lower in T1DMob (9.7±3.0) than T2DMad (13.9±2.4) (p Disclosure F. Barbetti: Consultant; Self; Amring. R. Bonfanti: Advisory Panel; Self; Abbott, Medtronic, Roche Diabetes Care. D. Iafusco: None.

Homozygous mutation of Insulin receptor (INS-R) gene cause an extremely rare disease called Leprechaunism, and induce intrauterine growth restriction with poor postnatal growth, hyperinsulinemia, postprandial hyperglycaemia, pre-prandial hypoglycaemia, typical facies, lack of subcutaneous fat, thick skin, hypertrichosis, macrogenitosomia in males. The survival is severely compromised in these patients. Treatment with diazoxide could ameliorate glycaemic control, however these patients are signed by a high precocious lethality into the first 1-2 years of life. Anecdotical cases are described with a longer survival. We describe the clinical case of a child with Leprechaunism, born from consanguineous parents, who had a homozygous mutation of the INS-R gene: c.3289 C>T (CAG->TAG) p.Gln 10975 stop (Q1097X). He was treated with diazoxide (5 mg/kg/day) and captopril (0.04 mg/kg/day), with a reduction of hyperglycaemia and hypertension. However, the stop in ponderal and linear growth induced to try the off-label treatment with mecasermin (0.04 mg/kg bid). The dose was progressively increased to 0.06 mg/kg/bid. After 2 years of treatment with mecasermin, the child increased the weight to 5.9 kg, length to 65 cm, head circumference to 41 cm. His neuromotor development is significantly improved. He performed an encephalic MRI which showed non-specific alterations of the white matter subcortical and periventricular, possible evolution of neonatal prolonged hypoglycaemic events. The peculiar outcome of our patient is linked to the long-term survival and the clinical improvement by mecasermin.

The heterotrimeric GTP-binding protein eIF2 forms a ternary complex with initiator methionyl-tRNA and recruits it to the 40S ribosomal subunit for start codon selection and thereby initiates protein synthesis. Mutations in EIF2S3, encoding the eIF2γ subunit, are associated with severe intellectual disability and microcephaly, usually as part of MEHMO syndrome.Exome sequencing of the X chromosome was performed on three related males with normal head circumferences and mild learning difficulties, hypopituitarism (GH and TSH deficiencies), and an unusual form of glucose dysregulation. In situ hybridisation on human embryonic tissue, EIF2S3-knockdown studies in a human pancreatic cell line, and yeast assays on the mutated corresponding eIF2γ protein, were performed in this study.We report a novel hemizygous EIF2S3 variant, p.Pro432Ser, in the three boys (heterozygous in their mothers). EIF2S3 expression was detectable in the developing pituitary gland and pancreatic islets of Langerhans. Cells lacking EIF2S3 had increased caspase activity/cell death. Impaired protein synthesis and relaxed start codon selection stringency was observed in mutated yeast.Our data suggest that the p.Pro432Ser mutation impairs eIF2γ function leading to a relatively mild novel phenotype compared with previous EIF2S3 mutations. Our studies support a critical role for EIF2S3 in human hypothalamo-pituitary development and function, and glucose regulation, expanding the range of phenotypes associated with EIF2S3 mutations beyond classical MEHMO syndrome. Untreated hypoglycaemia in previous cases may have contributed to their more severe neurological impairment and seizures in association with impaired EIF2S3. FUND: GOSH, MRF, BRC, MRC/Wellcome Trust and NIGMS funded this study.

Objectives: Mecasermin is recombinant human insulin-like growth factor 1 (IGF1) which is approved for the treatment of short stature in children with documented primary IGF1 deficiency. Leprechaunism, also known as Donohue syndrome, is a severe disease, secondary to a severe congenital insulin resistance, with prenatal and neonatal growth retardation, typical dysmorphic features, glycaemic dysregulation characterized by hyperinsulinemia and hyperandrogenism. These patients have a poor prognosis with death in the first year of life. Methods: We describe the case of a 3.5 years child, born at 35,4 weeks, with severe fetal growth restriction (weight 1149 gr; length: 38 cm; cranial circumference: 28 cm), typical facial features with low implant ears, low implant hairs, hypertrichosis, hypertrophic external genitalia, postnatal growth failure, and severe hyperglycaemia (327 mg/dl) alternated with hypoglycaemia (10 mg/dl) also during i.v. infusion of glucose; significant hyperinsulinism (1000 mcU/dl) with elevated C peptide levels (43,41 ng/ml), persistent hypertension (113/74 mmHg). He has consanguineous parents (cousins) and the mother underwent abortions before the baby was born. Results: A treatment with diazoxide (5 mg/kg/day) was tried with limited efficacy. He was treated with ACE-inhibitor (Captopril) at the dose of 0,02 mg/kg/day with a low response. The Captopril dose was increased at 0,04 mg/kg/day with a regulation of the blood pressure (76/54 mmHg). The genetic study of INS-R was showed a homozygote mutation in the insulin receptor (INS-R) gene. The mutation reported was c.3289C>T (CAG->TAG) p.Gln1097Stop (Q1097X). For the growth delay and the hypotrophic muscular masses he started a off-label treatment with mecasermin at increasing doses. He had no adverse events linked to the treatment. Otherwise, he improved growth and muscular strength. Conclusions: The singular case is of relieve for the rarity of the disease and for the good response to the treatment with mecasermin, the real opportunity for these children with a severe disease otherwise with a poor prognosis.

Insulin gene mutations, either dominant or recessive, can cause permanent neonatal diabetes mellitus (INS/PNDM), which is defined as diabetes with onset within 6 months of birth [1, 2]. More rarely, INS dominant mutations give rise to diabetes that presents during infancy [3]. In most patients with heterozygous, dominant INS mutations, C-peptide is in the normal-low range at diabetes outset, but over time declines to undetectable levels as a consequence of ongoing apoptosis of the pancreatic beta cells. This process is triggered by the sustained endoplasmic reticulum (ER) stress [2] induced by misfolding of mutant insulin trapped inside the beta cell. Thus, at least in principle, strategies aimed at relieving ER stress of beta cells may help to preserve endogenous insulin production from the normal allele. During the last 8 years, we identified a total of 16 cases with dominant INS gene mutations from 13 different Italian centers [2–4]. Thirteen were diagnosed with INS/PNDM (or with diabetes with onset during infancy) (2–4 and FB unpublished observations) before year 2010 and were treated with standard insulin therapy. Currently, all of them show undetectable C-peptide values. Instead, the three patients diagnosed with a dominant INS mutation after year 2010 were started on continuous subcutaneous insulin infusion (CSII) within a week after diagnosis. The three patients carried the novel INS mutation c.149A>G, p.Tyr50Cys (patient 1) and the already described c.94G>A p.Gly32Ser (patient 2) and c.314T>C p.Leu105Pro (patient 3). Diabetes onset was at 1 month of age for patient 1, 7 months for patient 2, and 5 months and a half for patient 3. In patient 1, CSII was integrated with continuous (i.e., 24 h a day) glucose monitoring (CGM). CGM was set with alarms for hypoglycemia, with a 2-h automatic interruption of insulin delivery by the pump if glucose sensor detected a value ≤4.44 mmol/l (80 mg/dl), and for hyperglycemia, with increased insulin infusion over basal level (“correction factor”) of 0.025 U for every 5.55 mmol/l (100 mg/dl) above the glucose value of 8.33 mmol/l (150 mg/dl), in order to obtain the narrowest plasma glucose fluctuations possible. Patient 1 was discharged from the hospital after 1 month, patient 2 after 18 days, and patient 3 after 12 days. Informed consent was obtained from parents of patients. C-peptide was evaluated in patients 1 and 2 by two-site chemiluminescent immunometric assay. Assay employed for patient 1 (Liaison C-peptide, Diasorin, Saluggia, Italy) has a reported limit of detection of 0.01 ng/ml (0.003 nmol/l) and functional sensitivity of 0.03 ng/ml (0.01 nmol/l); for patient 2, the assay (Immulite 2000 C-Peptide, Siemens) has a reported limit of detection and functional sensitivity of 0.08 ng/ml (0.03 nmol/l). Blood samples for C-peptide determination were drawn after an overnight fast, without suspension of basal insulin infusion. At follow-up as outpatients, no allergic reaction, lipo-atrophy, or -hypertrophy at the site of catheter insertion were observed; in addition, no episodes of ketosis or severe hypoglycemia requiring new hospitalization were reported for any patient. HbA1c is not a reliable method to evaluate metabolic control below the age of 6 months, because of the interfering effect of fetal hemoglobin: consequently, we do not report on patient 1’s glycated hemoglobin during the first semester of CSII. HbA1c values determined in patients 1 and 2 six months after diabetes onset were nevertheless comparable: 50 mmol/mol (6.7 %) for patient 1 (age 7 months) and 48 mmol/mol (6.5 %) for patient 2 (age 13 months) (Table 1). At follow-up, HbA1c values 12, 18, and 24 months after diabetes onset were declining in patient 1, while patient 2 showed a more irregular pattern (Table 1). Of note, insulin dose used for patient 2 was much lower for the entire period of CSII treatment (Table 1), suggesting that patient 2 may be more insulin-sensitive than patient 1. At strong variance with patients 1 and 2, patient 3 showed very high HbA1c from diabetes onset and never reached optimal metabolic control (Table 1). Table 1 Insulin dose and HbA1c in the three patients during 24-month period of treatment with CSII Interestingly, C-peptide was measurable at diabetes onset (1.04 ng/ml or 0.35 nmol/l), but became undetectable in patient 2 (CSII only) after 12 and 24 months from diabetes diagnosis, consistent with other reports showing this pattern in patients with INS proteotoxic mutations [2, 3]. In contrast, after the initial decrement recorded the first month after diabetes presentation, C-peptide of patient 1 (integrated system CSII/CGM) increased with a current value at 24 months of age of 0.26 nmol/l (Fig. 1). However, it has to be noticed that because of different sensitivities between C-peptide assays utilized, a direct comparison of these two patients cannot be easily made. Nevertheless, this was a surprising finding that has no easy explanation. From the clinical standpoint, the effect of the p.Tyr50Cys mutation seemed more pronounced than p.Gly32Ser, because patient 1 had an earlier diabetes presentation combined with a higher plasma glucose at onset (509 vs 293 mg/dl of patient 2). Interestingly, five patients previously described who bear INS/G23S mutation had diabetes onset at 6 months of age or beyond [1, 3]. On the other side of the token, patient 1 had no HbA1c fluctuations (Table 1), and it is tempting to speculate that the reduction in patient’s glycemic excursions obtained with CSII/CGM integrated system may have led to a substantial reduction in beta cell apoptosis consequent to the alleviation of endoplasmic reticulum crowding [5]. Fig. 1 C-peptide plasma level of patient 1 during the 24-month period of integrated CSII–CGM system. Numbers below each point are glucose values (mg/dl) at the time of blood drawing The results presented here indicate that CSII alone as well as sensor-augmented CSII is a feasible—and safe—therapeutic strategy for neonates or infants with diabetes, not only in the hospital setting, but at home. Moreover, CSII–CGM integrated system may be superior to CSII only, though we acknowledge that more cases must be studied to draw any robust conclusion. This may be probably obtained only through an international collaborative study, taking into consideration that PNDM is a rare condition (1:200,000 live births in countries with low rate of consanguineous marriages) [4].