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Objective: Heterozygous coding sequence mutations of the INS gene are a cause of permanent neonatal diabetes (PNDM), requiring insulin therapy similar to T1D. While the negative effects on insulin processing and secretion are known, how dominant insulin mutations result in a continued decline of beta cell function after birth is not well understood., Methods: We explored the causes of beta cell failure in two PNDM patients with two distinct INS mutations using patient-derived iPSCs and mutated hESCs., Results: we detected accumulation of misfolded proinsulin and impaired proinsulin processing in vitro, and a dominant-negative effect of these mutations on beta-cell mass and function after transplantation into mice. In addition to anticipated ER stress, we found evidence of beta-cell dedifferentiation, characterized by an increase of cells expressing both Nkx6.1 and ALDH1A3, but negative for insulin and glucagon., Conclusions: These results highlight a novel mechanism, the loss of beta cell identity, contributing to the loss and functional failure of human beta cells with specific insulin gene mutations., Competing Interests: Declaration of competing interest Authors declare no conflicts of interest., (Copyright © 2024 The Author(s). Published by Elsevier GmbH.. All rights reserved.)

Introduction: Management of Type 1 Diabetes (T1D) poses numerous challenges, especially for young children and their families. Parental care positively influencesthe outcomesofchildren 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 < 0.05)., Conclusion: Our observational real-life study confirms the positive effect of parental care in T1D very young children and demonstrates that during the COVID-19 pandemic it was possible to obtain a good glycometabolic compensation despite the significant change in lifestyle., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)

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., (Copyright © 2018 The Author(s). Published by Elsevier Inc. All rights reserved.)

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., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Aims: Neonatal diabetes mellitus (NDM) is a rare disorder, and guidance is limited regarding its optimal management. We reviewed insulin usage in NDM, with a focus on continuous subcutaneous insulin infusion (CSII)., Methods: A PubMed search identified 40 reports of patients with NDM treated with insulin published between 1994 and 2016., Results: Data concerning treatment of NDM are limited. CSII resolves some of the issues associated with insulin therapy in neonates. No clinical trials of CSII in NDM have been reported. Case reports suggest that CSII is a safe and effective means of treating NDM. CSII was initiated to improve glycaemic control, for practicality and convenience, and to overcome difficulties associated with the maintenance of long-term intravenous catheters. CSII can provide better glycaemic control than multiple daily injections, with few hypoglycaemic events. Continuous glucose monitoring integrated with the pump helps provide more precise control of blood glucose levels. CSII generally uses short-acting insulin or rapid-acting insulin analogues, and those that are approved for use in neonates appear to be appropriate for the treatment of NDM using an insulin pump., Conclusions: Information from case reports indicates that CSII is safe and effective for the management of NDM., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Aims: Neonatal diabetes mellitus (NDM) is defined as hyperglycemia and impaired insulin secretion with onset within 6 months of birth. While rare, NDM presents complex challenges regarding the management of glycemic control. The availability of continuous subcutaneous insulin infusion pumps (CSII) in combination with continuous glucose monitoring systems (CGM) provides an opportunity to monitor glucose levels more closely and deliver insulin more safely., Methods: We report four cases of young infants with NDM successfully treated with CSII and CGM. Moreover, in two cases with Kir 6.2 mutation, we describe the use of CSII in switching therapy from insulin to sulfonylurea treatment., Results: Insulin pump requirement for the 4 neonatal diabetes cases was the same regardless of disease pathogenesis and c-peptide levels. No dilution of insulin was needed. The use of an integrated CGM system helped in a more precise control of BG levels with the possibility of several modifications of insulin basal rates. Moreover, as showed in the first two case-reports, when the treatment was switched from insulin to glibenclamide, according to identification of Kir 6.2 mutation and diagnosis of NPDM, the CSII therapy demonstrated to be helpful in allowing gradual insulin suspension and progressive introduction of sulfonylurea., Conclusions: During the neonatal period, the use of CSII therapy is safe, more physiological, accurate and easier for the insulin administration management. Furthermore, CSII therapy is safe during the switch of therapy from insulin to glibenclamide for infants with permanent neonatal diabetes mellitus.

A growing list of insulin gene mutations causing a new form of monogenic diabetes has drawn increasing attention over the past seven years. The mutations have been identified in the untranslated regions of the insulin gene as well as the coding sequence of preproinsulin including within the signal peptide, insulin B-chain, C-peptide, insulin A-chain, and the proteolytic cleavage sites both for signal peptidase and the prohormone convertases. These mutations affect a variety of different steps of insulin biosynthesis in pancreatic beta cells. Importantly, although many of these mutations cause proinsulin misfolding with early onset autosomal dominant diabetes, some of the mutant alleles appear to engage different cellular and molecular mechanisms that underlie beta cell failure and diabetes. In this article, we review the most recent advances in the field and discuss challenges as well as potential strategies to prevent/delay the development and progression of autosomal dominant diabetes caused by INS-gene mutations. It is worth noting that although diabetes caused by INS gene mutations is rare, increasing evidence suggests that defects in the pathway of insulin biosynthesis may also be involved in the progression of more common types of diabetes. Collectively, the (pre)proinsulin mutants provide insightful molecular models to better understand the pathogenesis of all forms of diabetes in which preproinsulin processing defects, proinsulin misfolding, and ER stress are involved., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

A permanent neonatal diabetes mellitus has finally been diagnosed through molecular genetics in two children and one adult after 9 to 35 years of uninterrupted insulin treatment. These patients developed diabetes before 6 months of age and were autoantibody negative. In one boy, a mutation in the KCNJ11 gene was identified at 9 years of age. In the other two patients (daughter and father, 12.6 and 25 years old respectively) the new gene variant (ABCC8/L213P) was found. Switching from insulin to sulfonylurea treatment leads to the definitive discontinuance of insulin therapy, improving metabolic control as well as the amelioration of the associated neurodevelopmental disabilities in the young girl in which an intermediate Development Delay, Epilepsy, Neonatal Diabetes syndrome was diagnosed.

Recently, missense mutations upstream of preproinsulin's signal peptide (SP) cleavage site were reported to cause mutant INS gene-induced diabetes of youth (MIDY). Our objective was to understand the molecular pathogenesis using metabolic labeling and assays of proinsulin export and insulin and C-peptide production to examine the earliest events of insulin biosynthesis, highlighting molecular mechanisms underlying β-cell failure plus a novel strategy that might ameliorate the MIDY syndrome. We find that whereas preproinsulin-A(SP23)S is efficiently cleaved, producing authentic proinsulin and insulin, preproinsulin-A(SP24)D is inefficiently cleaved at an improper site, producing two subpopulations of molecules. Both show impaired oxidative folding and are retained in the endoplasmic reticulum (ER). Preproinsulin-A(SP24)D also blocks ER exit of coexpressed wild-type proinsulin, accounting for its dominant-negative behavior. Upon increased expression of ER-oxidoreductin-1, preproinsulin-A(SP24)D remains blocked but oxidative folding of wild-type proinsulin improves, accelerating its ER export and increasing wild-type insulin production. We conclude that the efficiency of SP cleavage is linked to the oxidation of (pre)proinsulin. In turn, impaired (pre)proinsulin oxidation affects ER export of the mutant as well as that of coexpressed wild-type proinsulin. Improving oxidative folding of wild-type proinsulin may provide a feasible way to rescue insulin production in patients with MIDY.

Background: Insulin gene (INS) mutations have recently been described as a common cause of permanent neonatal diabetes (PNDM) and a rare cause of diabetes diagnosed in childhood or adulthood., Methods: INS was sequenced in 116 maturity-onset diabetes of the young (MODYX) patients (n = 48 Danish and n = 68 Czech), 83 patients with gestational diabetes mellitus (GDM), 34 type 1 diabetic patients screened negative for glutamic acid decarboxylase (GAD), and 96 glucose tolerant individuals. The control group was randomly selected from the population-based sampled Inter99 study., Results: One novel heterozygous mutation c.17G>A, R6H, was identified in the pre-proinsulin gene (INS) in a Danish MODYX family. The proband was diagnosed at 20 years of age with mild diabetes and treated with diet and oral hypoglycaemic agent. Two other family members who carried the INS R6H were diagnosed with diabetes when 51 years old and with GDM when 27 years old, respectively. A fourth mutation carrier had normal glucose tolerance when 20 years old. Two carriers of INS R6H were also examined twice with an oral glucose tolerance test (OGTT) with 5 years interval. They both had a approximately 30% reduction in beta-cell function measured as insulinogenic index. In a Czech MODYX family a previously described R46Q mutation was found. The proband was diagnosed at 13 years of age and had been treated with insulin since onset of diabetes. Her mother and grandmother were diagnosed at 14 and 35 years of age, respectively, and were treated with oral hypoglycaemic agents and/or insulin., Conclusion: Mutations in INS can be a rare cause of MODY and we conclude that screening for mutations in INS should be recommended in MODYX patients.

Objective: Heterozygous, gain-of-function mutations of the insulin gene can cause permanent diabetes with onset ranging from the neonatal period through adulthood. The aim of our study was to screen for the insulin gene in patients who had been clinically classified as type 1 diabetic but who tested negative for type 1 diabetes autoantibodies., Research Design and Methods: We reviewed the clinical records of 326 patients with the diagnosis of type 1 diabetes and identified seven probands who had diabetes in isolation and were negative for five type 1 diabetes autoantibodies. We sequenced the INS gene in these seven patients., Results: In two patients whose diabetes onset had been at 2 years 10 months of age and at 6 years 8 months of age, respectively, we identified the mutation G(B8)S and a novel mutation in the preproinsulin signal peptide (A(Signal23)S)., Conclusions: Insulin gene mutations are rare in absolute terms in patients classified as type 1 diabetic (0.6%) but can be identified after a thorough screening of type 1 diabetes autoantibodies.

Permanent neonatal diabetes mellitus (PNDM) is a rare disorder usually presenting within 6 months of birth. Although several genes have been linked to this disorder, in almost half the cases documented in Italy, the genetic cause remains unknown. Because the Akita mouse bearing a mutation in the Ins2 gene exhibits PNDM associated with pancreatic beta cell apoptosis, we sequenced the human insulin gene in PNDM subjects with unidentified mutations. We discovered 7 heterozygous mutations in 10 unrelated probands. In 8 of these patients, insulin secretion was detectable at diabetes onset, but rapidly declined over time. When these mutant proinsulins were expressed in HEK293 cells, we observed defects in insulin protein folding and secretion. In these experiments, expression of the mutant proinsulins was also associated with increased Grp78 protein expression and XBP1 mRNA splicing, 2 markers of endoplasmic reticulum stress, and with increased apoptosis. Similarly transfected INS-1E insulinoma cells had diminished viability compared with those expressing WT proinsulin. In conclusion, we find that mutations in the insulin gene that promote proinsulin misfolding may cause PNDM.

The article "Editorial: Personalized therapies for monogenic diabetes" discusses the precision medicine approach to managing monogenic diabetes, focusing on Maturity Onset Diabetes of the Young (MODY), Neonatal Diabetes Mellitus (NDM), and Severe Insulin Resistance syndromes. It highlights the genetic variants responsible for these conditions and potential treatment options, such as oral hypoglycemic agents for MODY and sulfonylureas for NDM. The research also explores new treatments, like SGLT2 inhibitors for Rabson-Mendenhall syndrome, and the use of precision medicine in tailoring care for pregnant women with MODY. [Extracted from the article]

The article focuses on a rare cause of transient neonatal diabetes mellitus (TNDM) related to a spontaneous splicing mutation in the HNF1B gene. Topics include the clinical case of an Italian patient with TNDM associated with this mutation, the necessity of genetic investigation in TNDM cases negative to common genetic causes, and the recommendation for a strict follow-up of glucose levels after remission in HNF1B-TNDM cases to detect early relapse of hyperglycemia.

The discovery of insulin almost 100 years ago has resulted in a remarkable increase in lifespan and quality of life for patients with type 1 diabetes. The Joslin Medalist Study has allowed researchers to access and study patients (Medalists) with type 1 diabetes who have been insulin dependent for 50 years or more. In this issue of the JCI, Yu et al. evaluated HLA variants, autoantibody status, β cell function, C-peptide release, and monogenetic diabetes genes in a cohort of Medalists. Postmortem analysis of pancreata from Medalists revealed the presence of insulin-positive β cells in these patients. Moreover, some patients were still able to respond to metabolic stimuli despite long-term insulin dependence. Overall, the Medalist cohort was highly heterogenous, and genetic testing suggested that several patients would fall into categories other than type 1 diabetes on the basis of REVEL (rare exome variant ensemble learner) classification and may be able to transfer to other therapy options. [ABSTRACT FROM AUTHOR]

OBJECTIVE--To study the role of the ENPP1 Q121 variant on glucose homeostasis in whites from Italy. RESEARCH DESIGN AND METHODS--We conducted case-control studies in 764 adults (from two independent samples of 289 nonobese and 485 obese individuals) and 240 overweight/ obese children undergoing oral glucose tolerance testing (OGTT). Early-phase insulin secretion and insulin sensitivity (the insulinogenic index and the insulin sensitivity index) and their interplay (the disposition index) were calculated. RESULTS--In adult subjects, glucose profiles during OGTT were significantly (P = 2 x 10[sup -2]) different across K121Q genotype groups and higher in QQ than KK individuals (P = 5 x 10[sup -2]). The insulinogenic index was significantly reduced in QQ (18.5 ± 3.4) compared with both KK (31.6 ± 1.0; P = 2.2 x 10[sup -7]) and KQ (30.5 ± 1.5; P = 3.2 x 10[sup -6]) individuals. KQ individuals also showed a reduced insulin sensitivity index compared with KK subjects (P = 3.6 x 10[sup -2]). The disposition index was lower in QQ carriers than in KQ and KK individuals (P = 8 x 10[sup -3] and 4 x 10[sup -4], respectively) and lower in KQ than in KK individuals (P = 3 x 10[sup -2]). Data obtained in overweight/obese children were very similar to those observed in adults, with QQ individuals showing (compared with KQ and KK subjects) a reduced insulinogenic index (P = 7 x 10[sup -3] and 2 x 10[sup -2], respectively) and disposition index (P = 2 x 10[sup -2] and 7 x 10[sup -3], respectively). CONCLUSIONS--Homozygous carriers of the ENPP1 Q121 variant are characterized by an altered glucose homeostasis. Reduced early-phase insulin secretion and inefficient interplay between insulin secretion and sensitivity, which occur at early ages, are major determinants of this defect. Diabetes 57: 3360-3364, 2008 [ABSTRACT FROM AUTHOR]

In this study, a second case of hyperinsulinemic hypoglycemia due to activation of glucokinase is reported. The 14-year-old proband had a history of neonatal hypoglycemia, treated with diazoxide. He was admitted with coma and convulsions due to nonketotic hypoglycemia. His BMI was 34 kg/m(2), and his fasting blood glucose ranged from 2.1 to 2.7 mmol/l, associated with inappropriately high serum levels of insulin, C-peptide, and proinsulin. An oral glucose tolerance test (OGTT) showed exaggerated responses of these peptides followed by profound hypoglycemia. Treatment with diazoxide and chlorothiazide was effective. His mother never had clinical hypoglycemic symptoms, even though her fasting blood glucose ranged from 2.9 to 3.5 mmol/l. Increases in serum insulin, C-peptide, and proinsulin in response to an OGTT suggested a lower threshold for glucose-stimulated insulin release (GSIR). Screening for mutations in candidate genes revealed a heterozygous glucokinase mutation in exon 10, substituting valine for alanine at codon 456 (A456V) in the proband and his mother. The purified recombinant glutathionyl S-transferase fusion protein of the A456V glucokinase revealed a decreased glucose S(0.5) (the concentration of glucose needed to achieve the half-maximal rate of phosphorylation) from 8.04 (wild-type) to 2.53 mmol/l. The mutant's Hill coefficient was decreased, and its maximal specific activity k(cat) was increased. Mathematical modeling predicted a markedly lowered GSIR threshold of 1.5 mmol/l. The theoretical and practical implications are manifold and significant. [ABSTRACT FROM AUTHOR]

The finding of a reduced insulin-stimulated glucose uptake and glycogen synthesis in the skeletal muscle of glucose-tolerant first-degree relatives of patients with NIDDM, as well as in cultured fibroblasts and skeletal muscle cells isolated from NIDDM patients, has been interpreted as evidence for a genetic involvement in the disease. The mode of inheritance of the common forms of NIDDM is as yet unclear, but the prevailing hypothesis supports a polygenic model. In the present study, we tested the hypothesis that the putative inheritable defects of insulin-stimulated muscle glycogen synthesis might be caused by genetic variability in the genes encoding proteins shown by biochemical evidence to be involved in insulin-stimulated glycogen synthesis in skeletal muscle. In 70 insulin-resistant Danish NIDDM patients, mutational analysis by reverse transcription-polymerase chain reaction-single strand conformation polymorphism-heteroduplex analysis was performed on genomic DNA or skeletal muscle-derived cDNAs encoding glycogenin, protein phosphatase inhibitor-1, phophatase targeting to glycogen, protein kinase B-alpha and -beta, and the phosphoinositide-dependent protein kinase-1. Although a number of silent variants were identified in some of the examined genes, we found no evidence for the hypothesis that the defective insulin-stimulated glycogen synthesis in skeletal muscle in NIDDM is caused by structural changes in the genes encoding the known components of the insulin-sensitive glycogen synthesis pathway of skeletal muscle. [ABSTRACT FROM AUTHOR]

Leptin, a hormone secreted by adipocytes, decreases food intake and increases energy expenditure. The role of insulin in the regulation of leptin secretion is poorly understood and is still a topic of debate. Insulin increases leptin mRNA synthesis in rodents, but in humans, the available data are discordant. To investigate the role of chronic hyperinsulinemia in the regulation of plasma leptin concentrations, we studied 13 patients with surgically confirmed insulinoma before and after tumor removal, along with 15 healthy control subjects matched for sex, age, and BMI. Immunoreactive plasma leptin levels were measured by radioimmunoassay; leptin mRNA levels were also determined by reverse transcription-competitive polymerase chain reaction in a subgroup of six patients with insulinoma and six control subjects. All determinations were made with subjects in the fasting state. Plasma leptin concentrations correlated positively with leptin mRNA levels (r = 0.880, P < 0.001). Leptin levels, both plasma protein and mRNA, were significantly higher in the insulinoma patients than in the control subjects (plasma protein: 17.5 +/- 3.6 vs. 2.9 +/- 0.4 ng/ml, respectively, P < 0.001; mRNA: 0.98 +/- 0.33 vs. 0.19 +/- 0.064 amol/microg RNA, respectively, P < 0.05), and they correlated positively with fasting plasma insulin levels in the patients with insulinoma (plasma protein: r = 0.686, P < 0.01; mRNA: 0.796, P < 0.05). Finally, removal of the insulin-secreting tumor was followed by the normalization of plasma leptin levels. In summary, in patients with insulinoma, 1) plasma leptin levels and leptin mRNA are elevated; 2) a direct relationship exists between leptin, both circulating protein and mRNA, and insulin concentrations; and 3) plasma leptin returns to normal levels after tumor removal. These data, therefore, support a role for insulin in the chronic regulation of leptin gene expression. [ABSTRACT FROM AUTHOR]