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Neonatal diabetes mellitus with congenital hypothyroidism (NDH) syndrome (MIM# 610199) is a rare disease caused by autosomal recessive mutations in the GLIS3 gene. GLIS3 is an important transcription factor that might acts as both a repressor and activator of transcription. To date, 22 cases of NDH syndrome from 16 families and 11 countries have been described. Herein, we report a child who developed diabetes during the first week of age. Additionally, she suffered from congenital hypothyroidism, cardiac abnormalities, and polycystic kidney disease. Genetic analysis revealed that patient is a carrier of two novel heterozygous mutations, p.Pro444fsdelG (c.1330delC) and p.His647Arg (c.1940A > G) in the GLIS3 gene. Each was inherited from clinically healthy father and mother, respectively. Bioinformatic tools (SIFT, PolyPhen2, PROVEAN and SWISS‐MODEL) declared that the p.His647Arg (c.1940A > G) variant has strong detrimental effect and disturbs Kruppel‐like zinc finger domain. All but one so far described cases of NDH syndrome have been caused by homozygous of GLIS3, making the described case the second case of pathogenic, compound heterozygosity of GLIS3 worldwide posing substantial clinical novelty and detailing an interesting interplay between the observed variants and GLIS3 expression, which seems to be autoregulated. Hence, the damaging missense mutation may further reduce the expression of any remaining functional alleles. This case report expands our understanding of the clinical phenotype, treatment approaches, and outcome of infants with GLIS3 mutations and indicates the need for further research to deepen our understanding of the role of GLIS3. [ABSTRACT FROM AUTHOR]

Monogenic forms of diabetes in children are frequently misclassified as either type 1 diabetes or young‐onset type 2 diabetes. There is a paucity of literature regarding pediatric monogenic diabetes in the Indian population. A retrospective analysis of case records of 37 children with monogenic diabetes who were diagnosed between 2008 and 2019 in a South Indian tertiary care center was performed. The write‐up describes the clinical, biochemical, and genetic characterization of these patients with the diagnoses of neonatal diabetes mellitus (15 patients), MODY (five patients), and various forms of syndromic diabetes (13 with Wolfram syndrome, two with H syndrome, one with mitochondrial diabetes, and one with thiamine responsive megaloblastic anemia). [ABSTRACT FROM AUTHOR]

Background: Maturity Onset Diabetes of the Young (MODY) constitutes a genetically and clinically heterogeneous type of monogenic diabetes. It is characterized by early onset, autosomal dominant inheritance and a defect in pancreatic β‐cell insulin secretion. To date, various MODY subtypes have been reported, each one of a distinct genetic etiology. Objective: The aim of this study was to identify the molecular defects of 50 patients with MODY employing the methodology of next generation sequencing (NGS) targeted gene panel. Methods: A panel of seven MODY genes was designed and employed to screen 50 patients fulfilling the MODY diagnostic criteria. Patients with no pathogenic, likely pathogenic or uncertain significance variants detected, were further tested by multiplex ligation‐dependent probe amplification (MLPA) for copy number variations (CNVs). Results: Eight different pathogenic or likely pathogenic variants were identified in eight MODY patients (diagnostic rate 16%). Five variants of uncertain significance were also detected in seven MODY patients. Five novel pathogenic and likely pathogenic variants were detected in the genes GCK; p.Cys371X, HNF1A; p.Asn402Tyr, HNF4A; p.Glu285Lys, and ABCC8; p.Met1514Thr and p.Ser1386Phe. Two de novo heterozygous deletions of the entire HNF1B gene were detected in two patients, raising the diagnostic rate to 20%. Conclusions: Although many MODY patients still remain without exact MODY type identification, the application of NGS methodology provided rapid results, increased diagnostic accuracy, and was cost‐effective compared to Sanger sequencing. Accurate genetic diagnosis of the MODY subtype is important for treatment selection, disease prognosis, and family counseling. [ABSTRACT FROM AUTHOR]

KLF11 is the causative gene for maturity‐onset diabetes of the young 7 (MODY7). KLF11 regulates insulin gene expression through binding to the GC box in the promoter. To date, only two KLF11 mutations have been identified in three families with early‐onset type 2 diabetes. Here, we report a novel KLF11 variant associated with early childhood‐onset type 1B diabetes. The proband and his younger sister exhibited hyperglycemia at age 1 year, and their mother developed diabetes at age 4 years. These three individuals required insulin injection from the initial phase of the disease. Being negative for islet cell autoantibodies, they were diagnosed with type 1B diabetes. Mutation screening for 30 diabetes‐associated genes identified a heterozygous KLF11 variant (p.His418Gln) in the proband and his sister. The variant was also detected in the affected mother, as well as in the allegedly unaffected maternal grandmother. In silico analyses indicated that this variant involves a highly conserved histidine residue in the first C2H2 zinc finger domain which ligates a zinc ion. In vitro analyses showed that expression levels and intracellular localization of His418Gln‐KLF11 were comparable to those of wildtype (WT)‐KLF11. Luciferase assays demonstrated that while WT‐KLF11 suppressed the activity of a 6 × GC box‐containing reporter, His418Gln‐KLF11 lacked the suppressive effect. Notably, His418Gln‐KLF11 canceled the suppressive effect of co‐transfected WT‐KLF11. Such a dominant‐negative effect was absent in the previously reported Ala347Ser‐KLF11 variant. These results indicate that specific variants of KLF11 (MODY7) with a dominant‐negative effect underlie early childhood‐onset type 1B diabetes with incomplete penetrance. This study documents a novel monogenic mutation associated with diabetes in children. [ABSTRACT FROM AUTHOR]

ABCC8 gene mutations with different inheritance patterns have been well described to cause transient and permanent forms of neonatal diabetes with onset of hyperglycemia commonly before the age of 6 months, and rare cases between 6 and 12 months. However, recent analyses have also demonstrated ABCC8 gene mutations in patients with monogenic diabetes (maturity onset diabetes of the young, MODY), with milder clinical phenotypes and later onset of hyperglycemia. We report two siblings with diabetes mellitus due to a novel homozygous p.(Phe1068Ile) (c.3202T>A) missense mutation of the ABCC8 gene, but significantly different phenotypes. The index case was diagnosed with diabetes due to an incidental finding of hyperglycemia at the age of 3 years, while her younger sibling presented with severe hyperglycemia and hyperosmolar dehydration at the age of 10 weeks. The possibility of a significant discordance in the correlation between genotype and phenotype needs to be taken into account when ABCC8 mutation dependent diabetes occurs within the same family. Genetic screening in children with diabetes from consanguineous family needs consideration, especially in case of negative autoantibodies and early onset of hyperglycemia. [ABSTRACT FROM AUTHOR]

Background: Results of genetic have led to off‐label glibenclamide treatment in patients with neonatal diabetes (NDM) because of potassium channel mutations. No pediatric form of glibenclamide was available. Glibenclamide was designated an orphan drug designation for NDM and a suspension was developed. As a part of the pediatric plan investigation, we assessed its acceptability, efficiency, and safety. Methods: In this Phase II, prospective, non‐randomized, single‐center study, patient received glibenclamide tablets for 1 month then the suspension for 3 months. We assessed acceptability using hedonic scales and patient questionnaires, effectiveness using glycated hemoglobin (HbA1C) assays and safety based on hypo and hyperglycemia, and other adverse events. Results: We included 10 patients (0.1‐16.2 years, 6 < 5 years) were included. Younger patients preferred the suspension and older the tablets. All parents were satisfied with the ease of suspension administration. The parents of 5 of 6 younger children preferred the suspension over the tablets and kept it. Switching from tablets to suspension did not affect the excellent metabolic control (median HbA1c change, −0.40%, [−1.3% to 0.5%] P = 0.08). Median frequencies of hypoglycemia and hyperglycemia were less than 5% of routine blood glucose assays and were similar with both dosage forms. Two patients each experienced one episode of hypoglycemia below 35 mg/dL highlighting the need for dosage titration when switching from tablets to suspension. Transient and non‐severe abdominal pain or diarrhea occurred in three patients. None of the patients discontinued the treatment. Conclusion: The glibenclamide oral suspension Amglidia, the first anti‐diabetic drug specifically developed for pediatric patients, is acceptable, effective, and safe in patients with NDM (NCT02375828). Clinical Trial Registration: Glibentek in Patients with Neonatal Diabetes Secondary to Mutations in K + ‐ATP Channels, clinicaltrials.gov, NCT02375828, https://clinicaltrials.gov/ct2/show/NCT02375828. [ABSTRACT FROM AUTHOR]

Objective: When diabetes is associated with congenital malformations, without autoimmune antibodies, a genetic cause is suspected. Here, we aimed to identify a defective gene that led to diabetes. Research Design and Methods: We performed an exome analysis of an index case and his healthy parents. Results: The child presented with childhood‐onset diabetes, congenital hypopituitarism, cardiac malformation, and anal atresia. A DNA analysis revealed a heterozygous de novo pathogenic variant in the developmental transcription factor, forkhead box A2 (FOXA2). The mutation resided in the DNA‐binding domain, which is highly conserved among species. Tridimensional molecular dynamics simulation modeling predicted an altered interaction between the mutated protein and DNA. Conclusions: A defect in the FOXA2 DNA‐binding domain was associated with childhood‐onset diabetes and multiple congenital anomalies, which reflected the pleiotropic nature of the gene. This report extends the recently described phenotype of neonatal hypoglycemia to later‐onset diabetes. We suggest to include FOXA2 analysis for neonatal hypoglycemia and to implement a long‐term follow‐up, particularly for the risk of diabetes. [ABSTRACT FROM AUTHOR]

Insulin gene (INS) mutations cause a rare form of maturity‐onset diabetes of the young (MODY), a heterogeneous group of autosomal dominant diabetes with at least 14 confirmed causative genes. Here, we describe a family with MODY due to a novel INS mutation, detected using massively parallel sequencing (MPS). The proband presented aged 11 years with mild diabetic ketoacidosis. She was negative for IA2 and GAD antibodies. She had a strong family history of diabetes affecting both her two siblings and her mother, none of whom had ketosis but who were considered to have type 1 diabetes and managed on insulin, and her maternal grandfather, who was managed for decades on sulfonylureas. Of note, her younger sister had insulin deficiency but an elevated fasting proinsulin:insulin ratio of 76% (ref 5%‐30%). Sanger sequencing of HNF4A, HNF1A, and HNF1B in the proband was negative. Targeted MPS using a custom‐designed amplicon panel sequenced on an Illumina MiSeq detected a heterozygous INS mutation c.277G>A (p.Glu93Lys). Sanger sequencing confirmed the variant segregated with diabetes within the family. Structural analysis of this variant suggested disruption of a critical hydrogen bond between insulin and the insulin receptor; however, the clinical picture in some individuals also suggested abnormal insulin processing and insulin deficiency. This family has a novel INS mutation and demonstrated variable insulin deficiency. MPS represents an efficient method of MODY diagnosis in families with rarer gene mutations. [ABSTRACT FROM AUTHOR]

Chromosome 6 abnormalities such as paternal uniparental isodisomy, paternal 6q24 duplication, and maternal DMR (differentially methylated region) hypomethylation are a common cause of transient neonatal diabetes mellitus (TNDM). Oral sulfonylurea (SU) is used off‐label to treat permanent neonatal diabetes mellitus owing to potassium channel mutation but has not been evaluated in TNDM. Our objective was to evaluate the efficacy and safety of SU therapy in chromosome 6‐related TNDM. Description of 3 case reports and literature review was the subject of the study. SU therapy was successful in 2 patients (initiated during neonatal life in 1 patient and during relapse in the other) but failed in the other despite the use of high dosage. The literature review identified 11 cases of patients with chromosome 6‐related TNDM treated with SU, including 4 treated before remission and 7 after the relapse. SU therapy was consistently effective, although 4 patients treated after the relapse required multiple oral medications. None of the patients needed associated insulin therapy. No side effects of SU or complications of diabetes were reported. SU seems effective and safe in chromosome 6‐related TNDM treatment when used to treat the initial episode of diabetes or the relapse. It improves patients’ and families’ quality of life. SU is available only as oral tablets. A pediatric dosage form would facilitate the treatment of neonates and infants. [ABSTRACT FROM AUTHOR]

Diabetes occurs in 1/90 000 to 1/160 000 births and when diagnosed under 6 months of age is very likely to have a primary genetic cause. FOXP3 encodes a transcription factor critical for T regulatory cell function and mutations are known to cause “immune dysregulation, polyendocrinopathy (including insulin‐requiring diabetes), enteropathy, X‐linked” (IPEX) syndrome. This condition is often fatal unless patients receive a bone‐marrow transplant. Here we describe the phenotype of male neonates and infants who had insulin‐requiring diabetes without other features of IPEX syndrome and were found to have mutations in FOXP3. Whole‐exome or next generation sequencing of genes of interest was carried out in subjects with isolated neonatal diabetes without a known genetic cause. RT‐PCR was carried out to investigate the effects on RNA splicing of a novel intronic splice‐site variant. Four male subjects were found to have FOXP3 variants in the hemizygous state: p.Arg114Trp, p.Arg347His, p.Lys393Met, and c.1044+5G>A which was detected in 2 unrelated probands and in a brother diagnosed with diabetes at 2.1 years of age. Of these, p.Arg114Trp is likely a benign rare variant found in individuals of Ashkenazi Jewish ancestry and p.Arg347His has been previously described in patients with classic IPEX syndrome. The p.Lys393Met and c.1044+5G>A variants are novel to this study. RT‐PCR studies of the c.1044+5G>A splice variant confirmed it affected RNA splicing by generating both a wild type and truncated transcript. We conclude that FOXP3 mutations can cause early‐onset insulin‐requiring diabetes with or without other features of IPEX syndrome. [ABSTRACT FROM AUTHOR]

Background: Neonatal diabetes mellitus (NDM) caused by mutations in KCNJ11 can be successfully treated with high dose oral sulfonylureas; however, little data is available on the risk of hypoglycemia. Objective: To determine the frequency, severity, and clinical significance of hypoglycemia in KCNJ11‐related NDM. Methods: Utilizing the University of Chicago Monogenic Diabetes Registry, parents completed an online questionnaire addressing hypoglycemia. Continuous glucose monitoring (CGM) data was available for 7 subjects. Results: Thirty subjects with KCNJ11‐related permanent NDM (166 patient‐years on sulfonylurea) had median sulfonylurea dose of 0.39 mg/kg/day (0.24‐0.88 IQR, interquartile range) with median HbA1c 5.7% (39 mmol/mol) (5.5‐6.1 IQR, 37‐43 mmol/mol). Hypoglycemia (<70 mg/dL) was reported monthly once or less frequently in 89.3% of individuals, but 3 (10.7%) reported once weekly or more. Of all hypoglycemic episodes reported, none involved seizures or unconsciousness and thus did not meet the current ISPAD definition of severe hypoglycemia. Seven individuals wore a CGM for a total of 912 hours with blood sugars falling below 70 mg/dL for 5.8% of the time recorded, similar to ranges reported for people without diabetes. Conclusions: In our cohort of KCNJ11‐related permanent NDM, hypoglycemia is infrequent and mild despite the high doses of sulfonylurea used and near‐normal level of glycemic control. Long‐term follow‐up on larger numbers will be required to clarify the incidence and determinants of hypoglycemia in this unique population. [ABSTRACT FROM AUTHOR]

Background Although type 1 diabetes ( T1D) remains the most frequent form of diabetes in individuals aged less than 20 years at onset, other forms of diabetes are being increasingly recognized. Objectives To describe the population of children with other forms of diabetes (non-type 1) included in the multinational SWEET (Better control in Pediatric and Adolescent diabete S: Working to cr Eate C En Ters of Reference) database for children with diabetes. Methods Cases entered in the SWEET database are identified by their physician as T1D, type 2 diabetes ( T2D) and other types of diabetes according to the ISPAD classification. Etiologic subgroups are provided for other types of diabetes. Descriptive analyses were tabulated for age at onset, gender, daily insulin doses, and hemoglobin A1c ( A1C) for each type and subtype of diabetes and when possible, values were compared. Results Of the 27 104 patients included in this report, 95.5% have T1D, 1.3% T2D, and 3.2% other forms of diabetes. The two most frequent etiologies for other forms of diabetes were maturity onset diabetes of the young ( MODY) ( n = 351) and cystic fibrosis-related diabetes ( CFRD) ( n = 193). The cause was unknown or unreported in 10% of other forms of diabetes. Compared with T1D, children with T2D and CFRD were diagnosed at an older age, took less insulin and had lower A1C (all P < .0001). Conclusion In centers included in SWEET, forms of diabetes other than type 1 remain rare and at times difficult to characterize. Sharing clinical information and outcome between SWEET centers on those rare forms of diabetes has the potential to improve management and outcome. [ABSTRACT FROM AUTHOR]

The article presents a part of the guidelines on pediatric diabetes in the International Society for Pediatric and Adolescent Diabetes (ISPAD) Clinical Practice Consensus Guidelines 2014 Compedium. It highlights the recommendations for diagnosis and management of monogenic diabetes in children and adolescents. It features the similar grading system used in the ISPAD guidelines with that of the American Diabetes Association.

Neonatal diabetes mellitus is known to have over 20 different monogenic causes. A syndrome of permanent neonatal diabetes along with primary microcephaly with simplified gyral pattern associated with severe infantile epileptic encephalopathy was recently described in two independent reports in which disease-causing homozygous mutations were identified in the immediate early response-3 interacting protein-1 ( IER3IP1) gene. We report here an affected male born to a non-consanguineous couple who was noted to have insulin-requiring permanent neonatal diabetes, microcephaly, and generalized seizures. He was also found to have cortical blindness, severe developmental delay and numerous dysmorphic features. He experienced a slow improvement but not abrogation of seizure frequency and severity on numerous anti-epileptic agents. His clinical course was further complicated by recurrent respiratory tract infections and he died at 8 years of age. Whole exome sequencing was performed on DNA from the proband and parents. He was found to be a compound heterozygote with two different mutations in IER3IP1: p.Val21Gly (V21G) and a novel frameshift mutation p.Phe27fsSer*25. IER3IP1 is a highly conserved protein with marked expression in the cerebral cortex and in beta cells. This is the first reported case of compound heterozygous mutations within IER3IP1 resulting in neonatal diabetes. The triad of microcephaly, generalized seizures, and permanent neonatal diabetes should prompt screening for mutations in IER3IP1. As mutations in genes such as NEUROD1 and PTF1A could cause a similar phenotype, next-generation sequencing approaches-such as exome sequencing reported here-may be an efficient means of uncovering a diagnosis in future cases. [ABSTRACT FROM AUTHOR]

Objective Maturity-Onset Diabetes of the Young ( MODY) is the most common type of monogenic diabetes accounting for 1-2% of the population with diabetes. The relative incidence of HNF1A- MODY ( MODY3) is high in European countries; however, data are not available for the Greek population. The aims of this study were to determine the relative frequency of MODY3 in Greece, the type of the mutations observed, and their relation to the phenotype of the patients. Design and methods Three hundred ninety-five patients were referred to our center because of suspected MODY during a period of 15 yr. The use of Denaturing Gradient Gel Electrophoresis of polymerase chain reaction amplified DNA revealed 72 patients carrying Glucokinase gene mutations ( MODY2) and 8 patients carrying HNF1A gene mutations ( MODY3). After using strict criteria, 54 patients were selected to be further evaluated by direct sequencing or by multiplex ligation probe amplification ( MLPA) for the presence of HNF1A gene mutations. Results In 16 unrelated patients and 13 of their relatives, 15 mutations were identified in the HNF1A gene. Eight of these mutations were previously reported, whereas seven were novel. Clinical features, such as age of diabetes at diagnosis or severity of hyperglycemia, were not related to the mutation type or location. Conclusions In our cohort of patients fulfilling strict clinical criteria for MODY, 12% carried an HNF1A gene mutation, suggesting that defects of this gene are responsible for a significant proportion of monogenic diabetes in the Greek population. No clear phenotype-genotype correlations were identified. [ABSTRACT FROM AUTHOR]

Background The etiology of type 1 diabetes ( T1D) is heterogeneous and is according to presence or absence of pancreatic autoantibodies divided into two subtypes: type 1A (autoimmune-mediated) and type 1B (non-autoimmune-mediated). Although several genes have been linked to type 1A diabetes, the genetic cause of type 1B diabetes in Japanese individuals is far from understood. Objective The aim of this study was to test for monogenic forms of diabetes in auto antibody-negative Japanese children with T1D. Methods Thirty four (19 males and 15 female) unrelated Japanese children with glutamate decarboxylase ( GAD) 65 antibodies and/or IA-2A-negative T1D and diabetes diagnosed at < 5 yr of age were recruited from 17 unrelated hospitals participating in the Japanese Study Group of Insulin Therapy for children and adolescent diabetes ( JSGIT). We screened the INS gene and the KCNJ11 gene which encode the ATP-sensitive potassium cannel by direct sequencing in 34 Japanese children with T1D. Results We identified three novel ( C31Y, C96R, and C109F) mutations and one previously reported mutation ( R89C) in the INS gene in five children, in addition to one mutation in the KCNJ11 gene ( H46R) in one child. These mutations are most likely pathogenic and therefore the cause of diabetes in carriers. Conclusion Our results suggest that monogenic forms of diabetes, particularly INS gene mutations, can be detected in Japanese patients classified with type 1B. Mutation screening, at least of the INS gene, is recommended for Japanese patients diagnosed as autoantibody negative at <5 yr of age. [ABSTRACT FROM AUTHOR]

Habeb AM, Al-Magamsi MSF, Eid IM, Ali MI, Hattersley AT, Hussain K, Ellard S. Incidence, genetics, and clinical phenotype of permanent neonatal diabetes mellitus in northwest Saudi Arabia. Background: Permanent neonatal diabetes mellitus (PNDM) in European population has an incidence of at least 1 in 260 000 live births and is most commonly due to mutations in KCNJ11 and ABCC8. However, data on this condition in other populations are limited. Objective: To define the incidence, genetic aetiology, and clinical phenotype of PNDM in Al-Madinah region, northwest Saudi Arabia. Methods: Patients with PNDM diagnosed between 2001 and 2010 were identified and clinically phenotyped. Sequencing of KCNJ11, ABCC8, and INS were performed initially on all subjects, and EIF2AK3, GLIS3, SLC2A2, SLC19A2, GCK, IPF1, and NEUROD1 genes were sequenced according to the clinical phenotype. Results: In total, 17 patients from 11 consanguineous families were diagnosed with PNDM and the incidence was 1 in 21 196 live births. Six different mutations in four genes were identified, of which two GLIS3 and one SLC2A2 were novel and no patient had KCNJ11, ABCC8, or INS mutations. Fourteen (82.4%) patients had identifiable genetic aetiology and their PNDM was part of known autosomal-recessive syndromes including Wolcott Rallison (41.1%), neonatal diabetes and hypothyroidism (29.4%), Fanconi-Bickel (5.8%), and thiamine-responsive megaloblastic anaemia (5.8%). Two patients with isolated PNDM and one with intermediate developmental delay, epilepsy and neonatal diabetes had no identifiable cause. Conclusions: Al-Madinah region has the highest reported incidence of PNDM worldwide. In this region with high consanguinity, PNDM has different genetic aetiology and in the majority of cases presents as a part of rare familial autosomal-recessive syndrome rather than in isolation. [ABSTRACT FROM AUTHOR]

Background/objective: Mutations in KCNJ11, ABCC8, or INS are the cause of permanent neonatal diabetes mellitus in about 50% of patients diagnosed with diabetes before 6 months of age and in a small fraction of those diagnosed between 6 and 12 months. The aim of this study was to identify the genetic cause of diabetes in 77 consecutive patients referred to the University of Chicago with diabetes diagnosed before 1 yr of age. Methods: We used Oragene™ DNA Self-Collection kit to obtain a saliva sample for DNA. We sequenced the protein-coding regions of KCNJ11, ABCC8, and INS using standard methods. Results: We enrolled 32 patients diagnosed with diabetes before 6 months of age and 45 patients diagnosed between 6 and 12 months. We identified a mutation in KCNJ11 in 14 patients from 12 families and in INS in 7 patients from 4 families. Three of the patients with an INS mutation were diagnosed with diabetes between 6 and 12 months of age. Finally, we found that two patients had an abnormality of chromosome 6q24 associated with transient neonatal diabetes mellitus. Conclusions: We were able to establish a genetic cause of diabetes in 63% of patients diagnosed with diabetes before 6 months of age and in 7% of patients diagnosed between 6 and 12 months. Genetic testing, which is critical for guiding appropriate management, should be considered in patients diagnosed with diabetes before 1 yr of age, especially if they are autoantibody negative, although the presence of autoantibodies does not rule out a monogenic cause. [ABSTRACT FROM AUTHOR]