Cause Of Neonatal Diabetes Mellitus Research Articles

What Do We Know about Neonatal Diabetes Caused by PDX1 Mutations?

Neonatal diabetes mellitus (NDM) is characterized by severe hyperglycemia, usually diagnosed in the first few months of an individual's life. It is a genetic disease and one of the main forms of monogenic diabetes. Changes in different genes have already been associated with NDM, including changes in the gene PDX1. In this review, we intend to summarize all neonatal diabetes cases caused by PDX1 mutations reported in the literature. For this purpose, we searched keywords in the literature from PubMed and articles cited by the HGMD database. The search retrieved 84 articles, of which 41 had their full text accessed. After applying the study exclusion criteria, nine articles were included. Of those articles, we detected thirteen cases of NDM associated with changes in PDX1; the majority in homozygous or compound heterozygous patients. Until now, variants in the PDX1 gene have been a rare cause of NDM; however, few studies have included the screening of this gene in the investigation of neonatal diabetes. In this review, we reinforce the importance of the PDX1 gene inclusion in genetic NGS panels for molecular diagnosis of NDM, and systematic morphological and functional exams of the pancreas when NDM is present.

A novel stop-loss mutation in NKX2-2 gene as a cause of neonatal diabetes mellitus: molecular characterization and structural analysis.

To identifythe genetic etiology of neonatal diabetes in an infant and to elucidate the molecular mechanism of the identified mutation underlying the pathogenesis. Genetic analysis was carried out by sequencing of known etiological genes associated with NDM. Molecular characterization was performed by constructing aidentified mutation inNKX2-2 geneand functional aspects wastested using transactivation, protein expression, DNA binding, nuclear localization assays. Structural analysis was performed bymodeling the NKX2-2 protein structure. A novel homozygous frameshift mutationc.772delC, p.Q258SFs*59in the NKX2-2 gene was identified in a patient with neonatal diabetes. Functional studies revealed that this mutation resulted in an elongated protein sequence, affecting DNA binding activity and transcriptional function. Structural analysis suggested alterations in the protein's tertiary structure, likely contributing to its dysfunction. This study presents the first report of a stop-loss mutation in the NKX2-2 gene associated with NDM. Our findings emphasize the importance of functional and structural characterization to understand the biological consequences of such mutations. This comprehensive analysis provides insights into the molecular mechanisms underlying NDM and its clinical phenotype, which may aid in better diagnosis and management of patients with similar variants in the future.

The Role of ONECUT1 Variants in Monogenic and Type 2 Diabetes Mellitus.

ONECUT1 (also known as HNF6) is a transcription factor involved in pancreatic development and beta-cell function. Recently, biallelic variants in ONECUT1 were reported as a cause of neonatal diabetes mellitus (NDM) in 2 subjects and missense monoallelic variants were associated with type 2 diabetes and possibly maturity-onset diabetes of the young (MODY). Here we examine the role of ONECUT1 variants in NDM, MODY and Type 2 diabetes in large international cohorts of subjects with monogenic diabetes and >400,000 subjects from UK Biobank. We identified a biallelic frameshift ONECUT1 variant as the cause of NDM in one individual. However, we found no enrichment of missense or null ONECUT1 variants among 484 individuals clinically suspected of MODY, in whom all known genes had been excluded. Finally, using a rare variant burden test in the UK Biobank European cohort, we identified a significant association between heterozygous ONECUT1 null variants and type 2 diabetes (P=0.006) but did not find association between missense variants and type 2 diabetes. Our results confirm biallelic ONECUT1 variants as a cause of NDM and highlight monoallelic null variants as a risk factor for type 2 diabetes. These findings confirm the critical role of ONECUT1 in human beta-cell function.

Clinical and molecular characteristics of infantile-onset diabetes mellitus in Egypt.

Purpose In patients diagnosed with diabetes mellitus (DM) before the age of 12 months, there is an increasing recognition of diabetes caused by single-gene mutations, also known as monogenic diabetes of infancy or neonatal DM (NDM). This study aimed to classify patients at Alexandria University Children’s Hospital (AUCH) diagnosed with infantile-onset DM into type 1 DM (T1DM) or NDM and to detect differences in molecular characteristics of NDM patients at our center in comparison to other countries.Methods This retrospective/prospective observational study was conducted on 39 patients diagnosed with infantile-onset DM (age of onset ≤1 year) at AUCH from January 2003 to November 2020. The patients were divided into 2 groups according to age at the onset of DM: ≤6 months and >6–12 months. Molecular testing was done in patients diagnosed with DM at ≤6 months and those with negative autoantibodies.Results Twelve patients were diagnosed with DM at age ≤6 months and 27 patients were diagnosed between 6–12 months. Seventeen patients (43.6%) had T1DM, whereas 9 patients (23.1%) had genetically confirmed NDM, including 3 harboring novel mutations. The most common genetic causes of NDM were EIF2AK3 mutations (n=3), followed by KCNJ11 (n=2) and ABCC8 (n=2). Other mutations included SLC19A2 (n=1) and INS (n=1). Three patients with potassium ATP channel mutations were transferred from insulin to sulfonylurea treatment.Conclusions It is essential to identify patients with NDM clinically and confirm the diagnosis by molecular testing to distinguish them from T1DM as it helps in refining their management, predicting prognosis, and guiding genetic counseling.

Growth and development in monogenic forms of neonatal diabetes.

Neonatal diabetes mellitus (NDM) is a rare disorder in which 80-85% of infants diagnosed under 6 months of age will be found to have an underlying monogenic cause. This review will summarize what is known about growth and neurodevelopmental difficulties among individuals with various forms of NDM. Patients with NDM often have intrauterine growth restriction and/or low birth weight because of insulin deficiency in utero and the severity and likelihood of ongoing growth concerns after birth depends on the specific cause. A growing list of rare recessive causes of NDM are associated with neurodevelopmental and/or growth problems that can either be related to direct gene effects on brain development, or may be related to a variety of co-morbidities. The most common form of NDM results in spectrum of neurological disability due to expression of mutated KATP channels throughout the brain. Monogenic causes of neonatal diabetes are characterized by variable degree of restriction of growth in utero because of deficiency of insulin that depends on the specific gene cause. Many forms also include a spectrum of neurodevelopmental disability because of mutation-related effects on brain development. Longer term study is needed to clarify longitudinal effects on growth into adulthood.

Monogenic diabetes: a gateway to precision medicine in diabetes.

Monogenic diabetes refers to diabetes mellitus (DM) caused by a mutation in a single gene and accounts for approximately 1%-5% of diabetes. Correct diagnosis is clinically critical for certain types of monogenic diabetes, since the appropriate treatment is determined by the etiology of the disease (e.g., oral sulfonylurea treatment of HNF1A/HNF4A-diabetes vs. insulin injections in type 1 diabetes). However, achieving a correct diagnosis requires genetic testing, and the overlapping of the clinical features of monogenic diabetes with those of type 1 and type 2 diabetes has frequently led to misdiagnosis. Improvements in sequencing technology are increasing opportunities to diagnose monogenic diabetes, but challenges remain. In this Review, we describe the types of monogenic diabetes, including common and uncommon types of maturity-onset diabetes of the young, multiple causes of neonatal DM, and syndromic diabetes such as Wolfram syndrome and lipodystrophy. We also review methods of prioritizing patients undergoing genetic testing, and highlight existing challenges facing sequence data interpretation that can be addressed by forming collaborations of expertise and by pooling cases.

Neonatal Diabetes Mellitus.

Neonatal Diabetes (ND) mellitus is a rare genetic disease (1 in 90,000 live births). It is defined by the presence of severe hyperglycaemia associated with insufficient or no circulating insulin, occurring mainly before 6 months of age and rarely between 6 months and 1 year. Such hyperglycaemia requires either transient treatment with insulin in about half of cases, or permanent insulin treatment. The disease is explained by two major groups of mechanism: malformation of the pancreas with altered insulin-secreting cells development/survival or abnormal function of the existing pancreatic β cell. The most frequent genetic causes of neonatal diabetes mellitus with abnormal β cell function are abnormalities of the 6q24 locus and mutations of the ABCC8 or KCNJ11 genes coding for the potassium channel in the pancreatic β cell. Other genes are associated with pancreas malformation or insufficient β cells development or destruction of β cells. Clinically, compared to patients with an ABCC8 or KCNJ11 mutation, patients with a 6q24 abnormality have lower birth weight and height, are younger at diagnosis and remission, and have a higher malformation frequency. Patients with an ABCC8 or KCNJ11 mutation have neurological and neuropsychological disorders in all those tested carefully. Up to 86% of patients who go into remission have recurrent diabetes when they reach puberty, with no difference due to the genetic origin. All these results reinforce the importance of prolonged follow-up by a multidisciplinary pediatric team, and later doctors specializing in adult medicine. 90% of the patients with an ABCC8 or KCNJ11 mutation as well as those with 6q24 anomalies are amenable to a successful switch from insulin injection to oral sulfonylureas.

Functional characterization of activating mutations in the sulfonylurea receptor 1 (ABCC8) causing neonatal diabetes mellitus in Asian Indian children.

Gain-of-function of ATP-sensitive K+ (KATP ) channels because of mutations in the genes encoding SUR1 (ABCC8) or Kir6.2 (KCNJ11) is a major cause of neonatal diabetes mellitus (NDM). Our aim is to determine molecular defects in KATP channels caused by ABCC8 mutations in Asian Indian children with NDM by in vitro functional studies. Wild-type (WT; NM_000352.4) or mutant sulfonylurea receptor 1 (SUR1) and Kir6.2 were co-expressed in COSm6 cells. Biogenesis efficiency and surface expression of mutant channels were assessed by immunoblotting and immunostaining. The response of mutant channels to cytoplasmic ATP and ADP was assessed by inside-out patch-clamp recordings. The response of mutant channels to known KATP inhibitors in intact cells were determined by 86 Rb efflux assays. Five SUR1 missense mutations, D212Y, P254S, R653Q, R992C, and Q1224H, were studied and showed increased activity in MgATP/MgADP. Two of the mutants, D212Y and P254S, also showed reduced response to ATP4- inhibition, as well as markedly reduced surface expression. Moreover, all five mutants were inhibited by the KATP channel inhibitors glibenclamide and carbamazepine. The study shows the mechanisms by which five SUR1 mutations identified in Asian Indian NDM patients affect KATP channel function to cause the disease. The reduced ATP4- sensitivity caused by the D212Y and P254S mutations in the L0 of SUR1 provides novel insight into the role of L0 in channel inhibition by ATP. The results also explain why sulfonylurea therapy is effective in two patients and inform how it should be effective for the other three patients.

Identification of novel variants in neonatal diabetes mellitus genes in Egyptian patients with permanent NDM

Neonatal diabetes mellitus (NDM) is a monogenic form of diabetes resulting from mutations in more than 20 different genes encoding proteins playing a key role in the normal function of the pancreatic beta-cell. Mutations in the genes encoding the ATP-sensitive potassium channel, ABCC8, and KCNJ11 and insulin (INS) gene are the most common causes of NDM; however, in consanguineous populations, EIF2AK3 mutations are more common. Identification of the causative mutations by genetic testing is critical for appropriate management and to guide genetic counseling. To determine the genetic etiology of NDM in diabetic neonates and infants diagnosed before the age of 1 year and to describe their phenotype/genotype characteristics, DNA sequencing of coding regions and intronic boundaries of ABCC8, KCNJ11, INS, and EIF2AK3 genes was undertaken in 20 patients. Further, targeted next-generation sequencing was performed for other genes known to cause NDM. ABCC8 mutations were found in two patients (10%), with compound heterozygous mutations (p.N131 K/p.R598*) in one patient and a homozygous mutation (p.R1554Q) in the another patient. Heterozygous p.A174G and p.V59M mutations of KCNJ11 were identified in two patients (10%), and homozygous EIF2AK3 mutations were identified in two further patients (p.T905fs and p.R653T) (10%). No INS mutations were identified. Further testing identified a SLC19A2 mutation (p.W387*) in one patient (5%) and the same homozygous GCK mutation in two siblings (p.A188T). ABCC8, KCNJ11, and EIF2AK3 mutations were the main genetic causes of permanent NDM among Egyptian neonates.

Severe Wolcott-Rallison syndrome due to a nonsense mutation in the first exon EIF2AK3

Wolcott-Rallison syndrome is a rare autosomal recessive disease characterized by neonatal diabetes mellitus in combination with osteodysplasia and liver failure. This disease is the most common cause of neonatal diabetes mellitus in consanguineous families. Wolcott-Rallison syndrome is associated with mutations in the EIF2AK3, the gene encoding a transmembrane enzyme PERK (pancreatic endoplasmic reticulum kinase) which inhibits the synthesis of proteins in the event of misfolding in the endoplasmic reticulum. In addition to the core symptoms patients may develop multisystemic clinical manifestation including acute renal and liver failure, short stature, exocrine pancreatic insufficiency, neuro-motor deficit, hypothyroidism, anemia, neutropenia, recurrent hypoglycemia. The disease is characterized by high mortality, more than 50% of patients die from fulminant liver failure. The awareness of Wolcott-Rallison syndrome is extremely low due to the rarity of detection, however in view of the severity of the disease and the unfavorable prognosis patients with this syndrome require timely diagnosis and care of well-organized team of specialists.

The personalized approach to neonatal diabetes therapy depending on the genetic defect

Neonatal diabetes mellitus (NDM) is defined as a heterogeneous group of genetic disorders with onset before 6 months of age. Mutations in KATP channel genes (KCNJ11, ABCC8) and the insulin gene (INS) are the most common causes of NDM. Accurate molecular diagnosis of NDM has significant clinical importance as it may influence diabetes treatment, explain pleiotropic features and define the prognosis in the examined subject as well as in other family members .
 In this report we present the results of a genetic examination of 70 patients with NDM, generalized the experience of using sulfonylurea in patients with KCNJ11 and ABCC8 genes mutations for the period from 2009 to 2016. A correlation is shown between the type of mutation, the course of the disease, and the sensitivity of patients to glibenclamide.

Pancreas and gallbladder agenesis in a newborn with semilobar holoprosencephaly, a case report

BackgroundPancreatic agenesis is an extremely rare cause of neonatal diabetes mellitus and has enabled the discovery of several key transcription factors essential for normal pancreas and beta cell development.Case presentationWe report a case of a Caucasian female with complete pancreatic agenesis occurring together with semilobar holoprosencephaly (HPE), a more common brain developmental disorder. Clinical findings were later confirmed by autopsy, which also identified agenesis of the gallbladder. Although the sequences of a selected set of genes related to pancreas agenesis or HPE were wild-type, the patient’s phenotype suggests a genetic defect that emerges early in embryonic development of brain, gallbladder and pancreas.ConclusionsDevelopmental defects of the pancreas and brain can occur together. Identifying the genetic defect may identify a novel key regulator in beta cell development.

An Activating STAT3 Mutation Causes Neonatal Diabetes through Premature Induction of Pancreatic Differentiation

Activating germline mutations in STAT3 were recently identified as a cause of neonatal diabetes mellitus associated with beta-cell autoimmunity. We have investigated the effect of an activating mutation, STAT3K392R, on pancreatic development using induced pluripotent stem cells (iPSCs) derived from a patient with neonatal diabetes and pancreatic hypoplasia. Early pancreatic endoderm differentiated similarly from STAT3K392R and healthy-control cells, but in later stages, NEUROG3 expression was upregulated prematurely in STAT3K392R cells together with insulin (INS) and glucagon (GCG). RNA sequencing (RNA-seq) showed robust NEUROG3 downstream targets upregulation. STAT3 mutation correction with CRISPR/Cas9 reversed completely the disease phenotype. STAT3K392R-activating properties were not explained fully by altered DNA-binding affinity or increased phosphorylation. Instead, reporter assays demonstrated NEUROG3 promoter activation by STAT3 in pancreatic cells. Furthermore, proteomic and immunocytochemical analyses revealed increased nuclear translocation of STAT3K392R. Collectively, our results demonstrate that the STAT3K392R mutation causes premature endocrine differentiation through direct induction of NEUROG3 expression.

Case report: maternal mosaicism resulting in inheritance of a novel GATA6 mutation causing pancreatic agenesis and neonatal diabetes mellitus

BackgroundHaploinsufficiency of the GATA6 transcription factor gene was recently found to be the most common cause of pancreatic agenesis, a rare cause of neonatal diabetes mellitus. Although most cases are de novo, we describe three siblings with inherited GATA6 haploinsufficiency and the rare finding of parental mosaicism.Case PresentationThe proband was born at term with severe intrauterine growth restriction, the first child of non-consanguineous parents. Diabetes occurred on day of life 1 with pancreatic exocrine insufficiency noted at several months of age. Pancreatic agenesis with absent gallbladder was confirmed when he underwent congenital diaphragmatic hernia and intestinal malrotation repair. A patent ductus arteriosus and pulmonary stenosis were repaired in infancy. Neurocognitive development has been normal. A second pregnancy was terminated due to tetralogy of Fallot and pulmonary hypoplasia secondary to congenital diaphragmatic hernia. The fetus also demonstrated severe pancreatic hypoplasia, gallbladder agenesis and intestinal rotation abnormalities. Despite severe hypoplasia, the pancreas demonstrated normal islet histology. Another sibling was found to have multiple cardiac abnormalities, requiring procedural intervention. Given the proband’s spectrum of congenital anomalies, Sanger sequencing of the GATA6 gene was performed, revealing a novel heterozygous c.635_660del frameshift mutation (p.Pro212fs). The mutation is predicted to be pathogenic, resulting in inclusion of a premature stop codon and likely degradation of the gene transcript by nonsense-mediated decay. The abortus and the sibling with the cardiac defect were both found to have the mutation, while the father and remaining sibling were negative. The mother, who is healthy with no evidence of diabetes or cardiac disease, is mosaic for the mutation at a level of 11% in her peripheral leukocytes by next-generation sequencing.ConclusionWe highlight a rare mechanism of pancreatic agenesis, this being only the second report of parental mosaicism for a GATA6 mutation and one of a handful of inherited cases. We also further define the phenotypic variability of GATA6 haploinsufficiency, even in individuals carrying the same mutation. Mutations in GATA6 should be strongly considered in cases of diabetes due to pancreatic hypoplasia or agenesis, and potentially affected family members should be tested regardless of phenotype.

Scanning and analysis of the KATP channel mutations in 12 cases of infancy onset type 1 diabetes mellitus

Objective To screen the mutation of KATP channel mutations in Chinese pedigrees with infantile onset type 1 diabetes mellitus(T1DM) and neonatal diabetes mellitus. Methods A cohort of 12 children of infant onset T1DM and neonatal diabetes mellitus admitted into Beijing Children's Hospital between March 2004 and June 2013 were selected.PCR amplification and direct sequencing were used to analyze the 39 exons of ABCC8 gene and one exon of KCNJ11.And the mutational sites of the parents of the probands was sequenced in order to identify the inheritance. Results Analysis revealed ABCC8 mutation in 25%(3/12 cases) of the patients, a case of transient neonatal diabetes(TNDM), a case of permanent neonatal diabetes mellitus(PNDM) and a case of infant onset T1DM.All positive patients showed a known heterozygosis mutation in the ABCC8 gene(R1182Q, c.3545G>A, D209E, c.627C>G, E208K c. 622G>A). The residue R1182Q, which was located at a position involved in joining transmembrane domain 2 to nucleotide binding domain 2, the mutations E208K and D209E were located in the intracellular region that links the transmembrane domain with the gatekeeper module.All the three mutations were located throughout the cytoplasm part of SUR1 protein.The TNDM successfully transferred from insulin to oral sulfonylureas therapy. Conclusions There is a complex genetic pathogenesis in neonatal and infant-onset diabetes.The KATP channel activating mutations is one of the main causes of neonatal diabetes mellitus and may cause T1DM in infants in China.Oral Glibenclamide therapy seems highly effective for some patients with the KATP channel activating mutations. Key words: KATP channel; Infancy onset type 1 diabetes mellitus; Neonatal diabetes mellitus; Glibenclamide

Neonatal Hyperglycemia due to Transient Neonatal Diabetes Mellitus in Puerto Rico.

Neonatal hyperglycemia is a metabolic disorder found in the neonatal intensive care units. Neonatal diabetes mellitus (NDM) is a very uncommon cause of hyperglycemia in the newborn, occurring in 1 in every 400,000 births. There are two subtypes of neonatal diabetes mellitus: permanent neonatal diabetes mellitus (PNDM) and transient neonatal diabetes mellitus (TNDM). We describe a term, small for gestational age, female neonate with transient neonatal diabetes mellitus who presented with poor feeding tolerance and vomiting associated with hyperglycemia (385 mg/dL), glycosuria, and metabolic acidosis within the first 12 hours of life. The neonate was treated with intravenous insulin, obtaining a slight control of hyperglycemia. An adequate glycemia was achieved at 5 weeks of life. The molecular studies showed complete loss of maternal methylation at the TND differentially methylated region on chromosome 6q24. The etiology of this neonate's hyperglycemia was a hypomethylation of the maternal TND locus. A rare cause of neonatal diabetes mellitus must be considered if a neonate presents refractory hyperglycemia. To our knowledge, this is the first case reported in Puerto Rico of transient neonatal mellitus due to the uncommon mechanism of maternal hypomethylation of the TND locus. Its prevalence in Puerto Rico is unknown.

Detection of KCNJ11 Gene Mutations in a Family with Neonatal Diabetes Mellitus

Background: Activating mutations of potassium inwardly-rectifying channel, subfamily J, member 11 (KCNJ11), which encodes Kir6.2 (beta-cell adenosine triphosphate-sensitive potassium [KATP] channel subunit), have been associated with neonatal diabetes mellitus (NDM) in different studies. Treatment with oral sulfonylureas in place of exogenous insulin injections results in improved glycemic control in most patients carrying these mutations. Exploration of genetic causes of NDM occurring before the age of 6 months has been proposed as an important issue in identification of monogenic forms of diabetes, which might be critical in their therapeutic management, as a consequence.

Recessive SLC19A2 mutations are a cause of neonatal diabetes mellitus in thiamine-responsive megaloblastic anaemia

Permanent neonatal diabetes mellitus (PNDM) is diagnosed within the first 6 months of life, and is usually monogenic in origin. Heterozygous mutations in ABCC8, KCNJ11, and INS genes account for around half of cases of PNDM; mutations in 10 further genes account for a further 10%, and the remaining 40% of cases are currently without a molecular genetic diagnosis. Thiamine-responsive megaloblastic anaemia (TRMA), due to mutations in the thiamine transporter SLC19A2, is associated with the classical clinical triad of diabetes, deafness, and megaloblastic anaemia. Diabetes in this condition is well described in infancy but has only very rarely been reported in association with neonatal diabetes. We used a combination of homozygosity mapping and evaluation of clinical information to identify cases of TRMA from our cohort of patients with PNDM. Homozygous mutations in SLC19A2 were identified in three cases in which diabetes presented in the first 6 months of life, and a further two cases in which diabetes presented between 6 and 12 months of age. We noted the presence of a significant neurological disorder in four of the five cases in our series, prompting us to examine the incidence of these and other non-classical clinical features in TRMA. From 30 cases reported in the literature, we found significant neurological deficit (stroke, focal, or generalized epilepsy) in 27%, visual system disturbance in 43%, and cardiac abnormalities in 27% of cases. TRMA should be considered in the differential diagnosis of diabetes presenting in the neonatal period.

Management of diabetes mellitus in infants

Diabetes mellitus diagnosed during the first 2 years of life differs from the disease in older children regarding its causes, clinical characteristics, treatment options and needs in terms of education and psychosocial support. Over the past decade, new genetic causes of neonatal diabetes mellitus have been elucidated, including monogenic β-cell defects and chromosome 6q24 abnormalities. In patients with KCNJ11 or ABCC8 mutations and diabetes mellitus, oral sulfonylurea offers an easy and effective treatment option. Type 1 diabetes mellitus in infants is characterized by a more rapid disease onset, poorer residual β-cell function and lower rate of partial remission than in older children. Insulin therapy in infants with type 1 diabetes mellitus or other monogenic causes of diabetes mellitus is a challenge, and novel data highlight the value of continuous subcutaneous insulin infusion in this very young patient population. Infants are entirely dependent on caregivers for insulin therapy, nutrition and glucose monitoring, which emphasizes the need for appropriate education and psychosocial support of parents. To achieve optimal long-term metabolic control with low rates of acute and chronic complications, continuous and structured diabetes care should be provided by a multidisciplinary health-care team.

Pancreas hypoplasia: an unusual cause of neonatal diabetes mellitus and exocrine pancreas insufficiency – Case report and discussion

Neonatal Diabetes Mellitus (NDM) is a rare condition, occurring in 1: 300rsquor;000–400rsquor;000 live births. Only few cases of pancreatic hypoplasia or agenesis have been published as possible aetiology of NDM. Mutations in transcription factors involved in pancreas development were found in rare cases.