Neonatal Diabetes Mellitus: Novel Mutations

Neonatal diabetes mellitus around the world: Update 2024

Neonatal diabetes mellitus (NDM), defined as diabetes with an onset during the first 6 months of life, is a rare form of monogenic diabetes. The initial publications on this condition began appearing in the second half of the 1990s and quite surprisingly, the search for new NDM genes is still ongoing with great vigor. Between 2018 and early 2024, six brand new NDM-genes have been discovered (CNOT1, FICD, ONECUT1, PDIA6, YIPF5, ZNF808) and three genes known to cause different diseases were identified as NDM-genes (EIF2B1, NARS2, KCNMA1). In addition, NDM cases carrying mutations in three other genes known to give rise to diabetes during childhood have been also identified (AGPAT2, BSCL2, PIK3R1). As a consequence, the list of NDM genes now exceeds 40. This genetic heterogeneity translates into many different mechanism(s) of disease that are being investigated with state-of-the-art methodologies, such as induced pluripotent stem cells (iPSC) and human embryonic stem cells (hESC) manipulated with the CRISPR technique of genome editing. This diversity in genetic causes and the pathophysiology of diabetes dictate the need for a variety of therapeutic approaches. The aim of this paper is to provide an overview on recent achievements in all aspects of this area of research.

Transient diabetes mellitus with ABCC8 variant successfully treated with sulfonylurea: Two case reports and review of literature

BACKGROUND

Transient neonatal diabetes mellitus (TNDM) is a rare form of diabetes mellitus that usually presents within the first 6 mo of life. Patients often enter remission within several months, although relapse can occur later in life. Mutations in the ABCC8 gene, which encodes the sulfonylurea receptor 1 of the ATP-sensitive potassium channel in pancreatic beta cells, are associated with TNDM and permanent neonatal diabetes. This study describes a novel de novo c.3880C>T heterozygous ABCC8 variant that causes TNDM and can be treated with sulf-onylurea therapy.

CASE SUMMARY

We retrospectively analyzed 2 Chinese patients with TNDM who were diagnosed, treated, or referred for follow-up between September 2017 and September 2023. The patients were tested for mutations using targeted next-generation sequencing. Patients with neonatal diabetes mellitus caused by a c.3880C>T heterozygous missense variant in the ABCC8 gene have not been reported before. Both children had an onset of post-infectious diabetic ketoacidosis, which is worth noting. At a follow-up visit after discontinuing insulin injection, oral glyburide was found to be effective with no adverse reactions.

CONCLUSION

Early genetic testing of neonatal diabetes mellitus aids in accurate diagnosis and treatment and helps avoid daily insulin injections that may cause pain.

Natural history of Wolcott-Rallison syndrome: A systematic review and follow-up study

BACKGROUND AND AIMS

To systematically review the literature for reports on Wolcott-Rallison syndrome, focusing on the spectrum and natural history, genotype-phenotype correlations, patient and native liver survival, and long-term outcomes.

METHODS

PubMed, Livio, Google Scholar, Scopus and Web of Science databases were searched. Data on genotype, phenotype, therapy, cause of death and follow-up were extracted. Survival and correlation analyses were performed.

RESULTS

Sixty-two studies with 159 patients met the inclusion criteria and additional 30 WRS individuals were collected by personal contact. The median age of presentation was 2.5 months (IQR 2) and of death was 36 months (IQR 50.75). The most frequent clinical feature was neonatal diabetes in all patients, followed by liver impairment in 73%, impaired growth in 72%, skeletal abnormalities in 59.8%, the nervous system in 37.6%, the kidney in 35.4%, insufficient haematopoiesis in 34.4%, hypothyroidism in 14.8% and exocrine pancreas insufficiency in 10.6%. Episodes of acute liver failure were frequently reported. Liver transplantation was performed in six, combined liver-pancreas in one and combined liver-pancreas-kidney transplantation in two individuals. Patient survival was significantly better in the transplant cohort (p = .0057). One-, five- and ten-year patient survival rates were 89.4%, 65.5% and 53.1%, respectively. Liver failure was reported as the leading cause of death in 17.9% of cases. Overall survival was better in individuals with missense mutations (p = .013).

CONCLUSION

Wolcott-Rallison syndrome has variable clinical courses. Overall survival is better in individuals with missense mutations. Liver- or multi-organ transplantation is a feasible treatment option to improve survival.

Incidence, Phenotypes, and Genotypes of Neonatal Diabetes: A 16-Year Experience. The Rare Genetic Etiologies of Neonatal Diabetes Are Common in Sudan

Neonatal diabetes (ND) is a rare subtype of diabetes occurring in the first 6 months of life. High incidence has been reported among populations with high rates of consanguineous marriage. However, there is paucity of reported data from sub-Saharan African countries. We report the incidence, genotype, and phenotype of ND in a large cohort from Sudan and compare these findings to regional and international data. All infants with onset of diabetes in the first 6 months of life, attending one of the only two tertiary pediatric diabetes centers in Sudan, Gaafar Ibn Auf Pediatric Tertiary Hospital and Sudan Childhood Diabetes Center, during the period of January 2006 to December 2022 were included. Medical records were reviewed for demographic and clinical information. Genetic testing was performed for 48 patients by the Exeter Genomics laboratory in the UK and for one patient by the University of Cambridge, Metabolic Research Laboratories, UK. The estimated incidence was 4.8 per 100,000 live births. Forty-nine ND patients from 45 unrelated families were identified, and a genetic diagnosis was confirmed in 37 patients (75.5%) from 33 unrelated families. Consanguinity was reported in 34 families (75.6%). The commonest genetic cause for permanent neonatal diabetes was EIF2AK3 recessive variants causing Wolcott-Rallison syndrome (18.92%). Pathogenic variants in two recently identified genes, ZNF808 and NARS2, were found in three patients each (8.11%). Activating variants in KCNJ11 and ABCC8 were identified in four (10.81%) and two (5.41%) patients, respectively. Apart from hyperglycemia, the commonest clinical presentations included dehydration, failure to thrive, and diabetic ketoacidosis. ND in Sudan has a different pattern of etiologies compared to Western and Asian populations yet similar to some Arab countries with EIF2AK3 mutations being the commonest cause. Pathogenic variants in recently identified genes reflect the impact of genome sequencing on increasing the rate of genetic diagnosis.

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

INTRODUCTION

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.

METHODS

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.

RESULTS

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.

CONCLUSION

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 (dis)integrated stress response: Genetic diseases of eIF2α regulators

The integrated stress response (ISR) is a conserved mechanism by which eukaryotic cells remodel gene expression to adapt to intrinsic and extrinsic stressors rapidly and reversibly. The ISR is initiated when stress-activated protein kinases phosphorylate the major translation initiation factor eukaryotic translation initiation factor 2ɑ (eIF2ɑ), which globally suppresses translation initiation activity and permits the selective translation of stress-induced genes including important transcription factors such as activating transcription factor 4 (ATF4). Translationally repressed messenger RNAs (mRNAs) and noncoding RNAs assemble into cytoplasmic RNA-protein granules and polyadenylated RNAs are concomitantly stabilized. Thus, regulated changes in mRNA translation, stability, and localization to RNA-protein granules contribute to the reprogramming of gene expression that defines the ISR. We discuss fundamental mechanisms of RNA regulation during the ISR and provide an overview of a growing class of genetic disorders associated with mutant alleles of key translation factors in the ISR pathway. This article is categorized under: RNA Interactions with Proteins and Other Molecules > Protein-RNA Interactions: Functional Implications RNA in Disease and Development > RNA in Disease Translation > Translation Regulation RNA in Disease and Development > RNA in Development.