Transient neonatal diabetes mellitus (TNDM) is a genetically heterogeneous form of neonatal diabetes characterized by hyperglycemia that remits during infancy with a tendency to recur in later life. This case report presents the history of a male infant with transient neonatal diabetes mellitus. The patient was treated with a continuous subcutaneous insulin infusion (CSII) and a continuous glucose monitoring (CGM) system until the age of 2 months, when the normoglycemia connected with a withdrawal of treatment was noted. The genetic test results excluded the majority of known mutations related to TNDM. This case report focuses on various genetic mutations and the clinical features connected with them that cause TNDM and highlights the difficulties in the diagnostic and therapeutic processes of this disease. CSII and CGM systems seem to be a safe and effective treatment option in TNDM and may be used in the therapy.

Monogenic diabetes, constituting 1%-2% of global diabetes cases, arises from single gene defects with distinctive inheritance patterns. Despite over 50 ass-ociated genetic disorders, accurate diagnoses and management of monogenic diabetes remain inadequate, underscoring insufficient clinician awareness. The disease spectrum encompasses maturity-onset diabetes of the young (MODY), characterized by distinct genetic mutations affecting insulin secretion, and neonatal diabetes mellitus (NDM) - a heterogeneous group of severe hyperglycemic disorders in infants. Mitochondrial diabetes, autoimmune monogenic diabetes, genetic insulin resistance and lipodystrophy syndromes further diversify the monogenic diabetes landscape. A tailored approach based on phenotypic and biochemical factors to identify candidates for genetic screening is recommended for suspected cases of MODY. NDM diagnosis warrants immediate molecular genetic testing for infants under six months. Identifying these genetic defects presents a unique opportunity for precision medicine. Ongoing research aimed to develop cost-effective genetic testing methods and gene-based therapy can facilitate appropriate identification and optimize clinical outcomes. Identification and study of new genes offer a valuable opportunity to gain deeper insights into pancreatic cell biology and the pathogenic mechanisms underlying common forms of diabetes. The clinical review published in the recent issue of World Journal of Diabetes is such an attempt to fill-in our knowledge gap about this enigmatic disease.

UNASSIGNED: Diabetes is a chronic disorder with a complex pathogenetic background including monogenic, polygenic, and environmental causes.
UNASSIGNED: The aim of the present paper is to share the information related to genetic and clinical data of large pediatric diabetes cohort.
UNASSIGNED: The present study retrospectively analyzes genetic and clinical findings of subjects diagnosed with diabetes under the age of 18 year and are in follow-up in a pediatric diabetes referral center.
UNASSIGNED: Out of 1205 children with diabetes (902 treated with insulin) 246 underwent genetic tests on the basis of clinical selection criteria since 2007.
UNASSIGNED: One hundred and ten variants related to diabetes were found in 89 of them. Age at presentation was 9.5±4.02 years (F/M 44/45). In total 49 pathogenic and likely pathogenic, 11 \"hot and warm\" of unknown significance variants were found in fourteen MODY and fifteen non-MODY genes according to criteria developed by American College of Medical Genetics. Thirty novel mutations were found. GCK (26.6%) and ABCC8 (10%) were two most frequently affected genes. Antibody testing revealed negative results in 80% of cases.
UNASSIGNED: Genetic interpretation in selected cases is important to understand the nature of the disease better. Improvement in testing opportunity and awareness might increase the prevalence of genetically explained diabetes cases. The distribution of subtypes differs between countries and even regions of the same country.

UNASSIGNED: Monogenic diabetes (MD) is caused by a mutation in a single gene and accounts for approximately 2.5-6% of all diabetes cases. Maturity-onset diabetes of the young (MODY) is the most common form of MD. To date, 14 different genes have been identified and associated with the presence of MODY phenotype. However, the number of potential candidate genes with relevance to beta cell function and glucose metabolism is increasing as more research is published. The aim of the study was to identify potentially causative variants in selected candidate genes in patients with a clinical diagnosis of MD.
UNASSIGNED: Targeted Next-Generation Sequencing (tNGS) on Illumina NextSeq 550 platform involving Agilent SureSelectQXT Target Enrichment protocol for 994 patients with suspected MD was performed. In the next step, the sequencing data of 617 patients with no pathogenic variants in main MD-related genes were reanalysed for the presence of causative variants in six candidate genes (MTOR, TBC1D4, CACNA1E, MNX1, SLC19A2, KCNH6). The presence of the selected variants was confirmed by Sanger sequencing.
UNASSIGNED: Seven heterozygous possibly damaging variants were identified in four candidate genes (MTOR, TBC1D4, CACNA1E, MNX1). Five changes were assessed as novel variants, not previously described in available databases. None of the described variants were present among patients previously diagnosed with MODY diabetes due to causative, pathogenic variants in known MODY-related genes.
UNASSIGNED: The results obtained seem to confirm the effectiveness of the NGS method in identifying potentially causative variants in novel candidate genes associated with MODY diabetes.

Development of the human pancreas requires the precise temporal control of gene expression via epigenetic mechanisms and the binding of key transcription factors. We quantified genome-wide patterns of DNA methylation in human fetal pancreatic samples from donors aged 6 to 21 post-conception weeks. We found dramatic changes in DNA methylation across pancreas development, with > 21% of sites characterized as developmental differentially methylated positions (dDMPs) including many annotated to genes associated with monogenic diabetes. An analysis of DNA methylation in postnatal pancreas tissue showed that the dramatic temporal changes in DNA methylation occurring in the developing pancreas are largely limited to the prenatal period. Significant differences in DNA methylation were observed between males and females at a number of autosomal sites, with a small proportion of sites showing sex-specific DNA methylation trajectories across pancreas development. Pancreas dDMPs were not distributed equally across the genome and were depleted in regulatory domains characterized by open chromatin and the binding of known pancreatic development transcription factors. Finally, we compared our pancreas dDMPs to previous findings from the human brain, identifying evidence for tissue-specific developmental changes in DNA methylation. This study represents the first systematic exploration of DNA methylation patterns during human fetal pancreas development and confirms the prenatal period as a time of major epigenomic plasticity.

UNASSIGNED: Mutations in the GCK gene cause Maturity Onset Diabetes of the Young (GCK-MODY) by impairing glucose-sensing in pancreatic beta cells. During pregnancy, managing this type of diabetes varies based on fetal genotype. Fetuses carrying a GCK mutation can derive benefit from moderate maternal hyperglycemia, stimulating insulin secretion in fetal islets, whereas this may cause macrosomia in wild-type fetuses. Modulating maternal glycemia can thus be viewed as a form of personalized prenatal therapy, highly beneficial but not justifying the risk of invasive testing. We therefore developed a monogenic non-invasive prenatal diagnostic (NIPD-M) test to reliably detect the transmission of a known maternal GCK mutation to the fetus.
UNASSIGNED: A small amount of fetal circulating cell-free DNA is present in maternal plasma but cannot be distinguished from maternal cell-free DNA. Determining transmission of a maternal mutation to the fetus thus implies sequencing adjacent polymorphisms to determine the balance of maternal haplotypes, the transmitted haplotype being over-represented in maternal plasma.
UNASSIGNED: Here we present a series of such tests in which fetal genotype was successfully determined and show that it can be used to guide therapeutic decisions during pregnancy and improve the outcome for the offspring. We discuss several potential hurdles inherent to the technique, and strategies to overcome these.
UNASSIGNED: Our NIPD-M test allows reliable determination of the presence of a maternal GCK mutation in the fetus, thereby allowing personalized in utero therapy by modulating maternal glycemia, without incurring the risk of miscarriage inherent to invasive testing.

The gain-of-function mutation in the TALK-1 K+ channel (p.L114P) is associated with maturity-onset diabetes of the young (MODY). TALK-1 is a key regulator of β-cell electrical activity and glucose-stimulated insulin secretion. The KCNK16 gene encoding TALK-1 is the most abundant and β-cell-restricted K+ channel transcript. To investigate the impact of KCNK16 L114P on glucose homeostasis and confirm its association with MODY, a mouse model containing the Kcnk16 L114P mutation was generated. Heterozygous and homozygous Kcnk16 L114P mice exhibit increased neonatal lethality in the C57BL/6J and the CD-1 (ICR) genetic background, respectively. Lethality is likely a result of severe hyperglycemia observed in the homozygous Kcnk16 L114P neonates due to lack of glucose-stimulated insulin secretion and can be reduced with insulin treatment. Kcnk16 L114P increased whole-cell β-cell K+ currents resulting in blunted glucose-stimulated Ca2+ entry and loss of glucose-induced Ca2+ oscillations. Thus, adult Kcnk16 L114P mice have reduced glucose-stimulated insulin secretion and plasma insulin levels, which significantly impairs glucose homeostasis. Taken together, this study shows that the MODY-associated Kcnk16 L114P mutation disrupts glucose homeostasis in adult mice resembling a MODY phenotype and causes neonatal lethality by inhibiting islet insulin secretion during development. These data suggest that TALK-1 is an islet-restricted target for the treatment for diabetes.

UNASSIGNED: We aimed to verify the usefulness of targeted next-generation sequencing (NGS) technology for diagnosing monogenic diabetes in a single center.
UNASSIGNED: We designed an amplicon-based NGS panel targeting 34 genes associated with known monogenic diabetes and performed resequencing in 56 patients with autoantibody-negative diabetes mellitus diagnosed at < 50 years who had not been highly obese. By bioinformatic analysis, we filtered significant variants based on allele frequency (< 0.005 in East Asians) and functional prediction. We estimated the pathogenicity of each variant upon considering the family history.
UNASSIGNED: Overall, 16 candidate causative variants were identified in 16 patients. Among them, two previously known heterozygous nonsynonymous single-nucleotide variants associated with monogenic diabetes were confirmed as causative variants: one each in the GCK and WFS1 genes. The former was found in two independent diabetes-affected families. Two novel putatively deleterious heterozygous variants were also assumed to be causative from the family history: one frameshift and one nonsynonymous single-nucleotide variant in the HNF4A gene. Twelve variants remained as candidates associated with the development of diabetes.
UNASSIGNED: Targeted NGS panel testing was useful to diagnose various forms of monogenic diabetes in combination with familial analysis, but additional ingenuity would be needed for practice.
UNASSIGNED: The online version contains supplementary material available at 10.1007/s13340-023-00669-3.

UNASSIGNED: Monogenic diabetes is a rare type of diabetes that is commonly misdiagnosed as type 1 or 2 diabetes mellitus, which adversely impacts patient care. Such cases are particularly challenging given the heterogeneity in presentation and overlap with other types of diabetes. As the sole use of meglitinides, especially repaglinide, to treat HNF1A-associated monogenic diabetes has been rarely reported in a few other observational studies, we describe a patient who was treated successfully with repaglinide.
UNASSIGNED: A 38-year-old woman with type 1 diabetes mellitus, congenital deafness, chronic kidney disease, and retinopathy presented with difficulty controlling her blood glucose levels. Although initially treated with insulin, she had periods of noncompliance with insulin without experiencing diabetic ketoacidosis. Although on insulin therapy, she experienced multiple episodes of hypoglycemia. The laboratory tests showed a hemoglobin A1c level of 10.8%, c-peptide level of 2.7 ng/mL (1.1-4.4 ng/mL), glucose level of 192 mg/dL, creatinine level of 1.23 ng/dL, and severely increased microalbumin-to-creatinine ratio of 638 mg/g (normal range, 0-29 mg/g). Pancreatic autoantibodies were negative. Genetic testing revealed a diagnosis of HNF1A-associated monogenic diabetes (c. 1340C>T (p.P447L)). She was ultimately treated with repaglinide after trials of sulfonylureas and dipeptidyl peptidase 4 inhibitors led to frequent hypoglycemia and a significant increase in the hemoglobin A1c level, respectively.
UNASSIGNED: This case highlights the importance of correctly diagnosing monogenic diabetes and reports the successful use of repaglinide to treat HNF1A-associated monogenic diabetes.
UNASSIGNED: Patients with HNF1A-associated monogenic diabetes who do not achieve euglycemia with sulfonylureas and insulin may be successfully treated with repaglinide monotherapy.

BACKGROUND: Heterozygous insulin receptor mutations (INSR) are associated with insulin resistance, hyperglycaemia and hyperinsulinaemic hypoglycaemia in addition to hyperandrogenism and oligomenorrhoea in women. Numerous autosomal dominant heterozygous mutations involving the INSR β-subunit tyrosine kinase domain resulting in type A insulin resistance have been previously described. We describe the phenotype, obstetric management and neonatal outcomes in a woman with type A insulin resistance caused by a mutation in the β-subunit of the INSR.
METHODS: We describe a woman with a p.Met1180Lys mutation who presents with hirsutism, oligomenorrhoea and diabetes at age 20. She has autoimmune thyroid disease, Coeliac disease and positive GAD antibodies. She is overweight with no features of acanthosis nigricans and is treated with metformin. She had 11 pregnancies treated with insulin monotherapy (n = 2) or combined metformin and insulin therapy (n = 9). The maximum insulin dose requirement was 134 units/day or 1.68 units/kg/day late in the second pregnancy. Mean birthweight was on the 37th centile in INSR positive offspring (n = 3) and the 94th centile in INSR negative offspring (n = 1).
CONCLUSIONS: The p.Met1180Lys mutation results in a phenotype of diabetes, hirsutism and oligomenorrhoea. This woman had co-existent autoimmune disease. Her insulin dose requirements during pregnancy were similar to doses observed in women with type 2 diabetes. Metformin may be used to improve insulin sensitivity in women with this mutation. Offspring inheriting the mutation tended to be smaller for gestational age.