Diagnosis and management of glucokinase monogenic diabetes in pregnancy: current perspectives

Monogenic diabetes: An evidence-based clinical approach

Monogenic diabetes is a heterogeneous disorder characterized by hyperglycemia arising from defects in a single gene. Maturity-onset diabetes of the young (MODY) is the most common type with 14 subtypes, each linked to specific mutations affecting insulin synthesis, secretion and glucose regulation. Common traits across MODY subtypes include early-onset diabetes, a family history of autosomal dominant diabetes, lack of features of insulin resistance, and absent islet cell autoimmunity. Many cases are misdiagnosed as type 1 and type 2 diabetes mellitus. Biomarkers and scoring systems can help identify candidates for genetic testing. GCK-MODY, a common subtype, manifests as mild hyperglycemia and doesn’t require treatment except during pregnancy. In contrast, mutations in HNF4A, HNF1A, and HNF1B genes lead to progressive beta-cell failure and similar risks of complications as type 2 diabetes mellitus. Neonatal diabetes mellitus (NDM) is a rare form of monogenic diabetes that usually presents within the first six months. Half of the cases are lifelong, while others experience transient remission. Permanent NDM is most commonly due to activating mutations in genes encoding the adenosine triphosphate-sensitive potassium channel (KCNJ11 or ABCC8) and can be transitioned to sulfonylurea after confirmation of diagnosis. Thus, in many cases, monogenic diabetes offers an opportunity to provide precision treatment. The scope has broadened with next-generation sequencing (NGS) technologies, replacing older methods like Sanger sequencing. NGS can be for targeted gene panels, whole-exome sequencing (WES), or whole-genome sequencing. Targeted gene panels offer specific information efficiently, while WES provides comprehensive data but comes with bioinformatic challenges. The surge in testing has also led to an increase in variants of unknown significance (VUS). Deciding whether VUS is disease-causing or benign can be challenging. Computational models, functional studies, and clinical knowledge help to determine pathogenicity. Advances in genetic testing technologies offer hope for improved diagnosis and personalized treatment but also raise concerns about interpretation and ethics.

Pregnancy and neonatal outcomes in women with GCK-MODY: an observational study based on standardised insulin modalities

AIMS/HYPOTHESIS

The management of GCK-MODY during pregnancy remains challenging. We evaluated the impact on pregnancy and neonatal outcomes of two standardised insulin strategies.

METHODS

In this prospective observational study, participants chose (in agreement with their physician) to be treated with insulin either when maternal capillary blood glucose (CBG) ≥ thresholds for gestational diabetes (5.3 mmol/l before or 6.7 mmol/l 2 h after meals) (MG group) or when fetal abdominal circumference ≥75th percentile (FG group). In the FG group, insulin was also initiated if CBG ≥ safety levels (6.7 mmol/l before meals or 11.1 mmol/l 2 h after meals). Data on glycaemic management, modalities and timing of insulin therapy and maternal and neonatal outcomes were recorded.

RESULTS

In the MG group (n=25), insulin was initiated more frequently (100% vs 75%, p=0.01) and earlier (p=0.001), with lower CBG and more frequent hypoglycaemic episodes compared with the FG group (n=21). However, there were no differences in pregnancy and neonatal outcomes. In the total cohort, the rate of large for gestational age (LGA) neonates, preterm deliveries and Caesarean sections was 22.2%, 2.2% and 40%, respectively. The rate of LGA was 0% among the neonates with the GCK variant vs 36% in those without (p=0.005). There were no associations between LGA and pregnancy characteristics, insulin therapy strategy or glycaemic management.

CONCLUSIONS/INTERPRETATION

In our study, the rate of LGA primarily depended on the fetal GCK genotype rather than the treatment strategy or glycaemic management. Our results suggest that a standardised strategy based on ultrasound monitoring of fetal growth and glycaemic safety thresholds, leading to delayed insulin initiation, offers a good fetal prognosis and minimises the risk of maternal hypoglycaemia.

TRIAL REGISTRATION

ClinTrials.gov NCT02556840.

Review of Monogenic Diabetes: Clinical Features and Precision Medicine in Genetic Forms of Diabetes

Monogenic diabetes is a group of diseases that encompasses a growing number of genetic abnormalities affecting pancreatic function/development leading to glycemic dysregulation. This includes conditions that have historically been referred to as maturity onset diabetes of the young or MODY in addition to neonatal diabetes mellitus. While recognition of a genetic or inherited form of diabetes has been known for decades, advances in molecular genetic testing have resulted in identification of specific forms of monogenic diabetes. Despite this, these genetic forms of diabetes remain widely underreported. It is important to be able to identify genetic forms of diabetes as treatment, monitoring for microvascular and macrovascular complications, and overall management varies for the different forms of monogenic diabetes. Furthermore, the identification of a specific monogenic form of diabetes can significantly impact the person's quality of life and other family members, as well as health care costs. This article highlights the identification, treatment, and management for various forms of monogenic diabetes and addresses some unmet needs in caring for people with monogenic forms of diabetes.

Pharmacological effect of ZYGK1, a novel glucokinase activator, in hyperglycemic and sulfonylurea-resistant type 2 diabetes in mice models

OBJECTIVES

Type 2 diabetes is caused due to inadequate glucose utilization in the liver and pancreas due to insulin resistance. Glucokinase enzyme plays a key role in metabolism of glucose and insulin release and hence glucokinase activation can be a useful therapeutic target for treatment of type 2 diabetes.

METHODS

Present study was conducted to investigate the effect of a novel glucokinase activator ZYGK1 in the preclinical models of diabetes in mice. The activity of ZYGK1 was evaluated using recombinant glucokinase, and isolated islets and hepatocytes. Acute effect on glucose disposal was evaluated in C57 mice and repeated dose effect was assessed in db/db mice, along with the evaluation in sulfonylurea-resistance db/db mice.

RESULTS

ZYGK1 has potent glucokinase stimulating activity with EC50 of 43 nM and increased glucokinase activity in islets and hepatocytes in a dose-related manner. Oral administration of ZYGK1 (0.1 to 10 mg/kg) showed dose dependently improved glucose disposal and glucose dependent insulin secretion in oral glucose tolerance test (OGTT) in C57 mice. Repeated dose administration of ZYGK1 improved glucose homeostasis and nondiabetic as well as diabetic mice and sulfonylurea-resistant db/db mice.

CONCLUSION

ZYGK1 appears to be a potential therapeutic option for the treatment of type 2 diabetes owing to its action in the liver and pancreas, and in conditions resistant to sulfonylurea therapy.

Management of monogenic diabetes in pregnancy: A narrative review

Pregnancy in women with monogenic diabetes is potentially complex, with significant implications for both maternal and fetal health. Among these, maturity-onset diabetes of the young (MODY) stands out as a prevalent monogenic diabetes subtype frequently encountered in clinical practice. Each subtype of MODY requires a distinct approach tailored to the pregnancy, diverging from management strategies in non-pregnant individuals. Glucokinase MODY (GCK-MODY) typically does not require treatment outside of pregnancy, but special considerations arise when a woman with GCK-MODY becomes pregnant. The glycemic targets in GCK-MODY pregnancies are not exclusively dictated by the maternal/paternal MODY genotype but are also influenced by the genotype of the developing fetus. During pregnancy, the choice between sulfonylurea or insulin for treating hepatocyte nuclear factor 1-alpha (HNF1A)-MODY and HNF4A-MODY depends on the mother's specific circumstances and the available expertise. Management of other rarer MODY subtypes is individualized, with decisions made on a case-by-case basis. Therefore, a collaborative approach involving expert diabetes and obstetric teams is crucial for the comprehensive management of MODY pregnancies.

A critical review on therapeutic approaches of CRISPR-Cas9 in diabetes mellitus

Diabetes mellitus (D.M.) is a common metabolic disorder caused mainly by combining two primary factors, which are (1) defects in insulin production by the pancreatic β-cells and (2) responsiveness of insulin-sensitive tissues towards insulin. Despite the rapid advancement in medicine to suppress elevated blood glucose levels (hyperglycemia) and insulin resistance associated with this hazard, a demand has undoubtedly emerged to find more effective and curative dimensions in therapeutic approaches against D.M. The administration of diabetes treatment that emphasizes insulin production and sensitivity may result in unfavorable side effects, reduced adherence, and potential treatment ineffectiveness. Recent progressions in genome editing technologies, for instance, in zinc-finger nucleases, transcription activator-like effector nucleases, and clustered regularly interspaced short palindromic repeat (CRISPR-Cas)-associated nucleases, have greatly influenced the gene editing technology from concepts to clinical practices. Improvements in genome editing technologies have also opened up the possibility to target and modify specific genome sequences in a cell directly. CRISPR/Cas9 has proven effective in utilizing ex vivo gene editing in embryonic stem cells and stem cells derived from patients. This application has facilitated the exploration of pancreatic beta-cell development and function. Furthermore, CRISPR/Cas9 enables the creation of innovative animal models for diabetes and assesses the effectiveness of different therapeutic strategies in treating the condition. We, therefore, present a critical review of the therapeutic approaches of the genome editing tool CRISPR-Cas9 in treating D.M., discussing the challenges and limitations of implementing this technology.

Dietary Sugar Research in Preschoolers: Methodological, Genetic, and Cardiometabolic Considerations

Excess dietary sugar intake increases the risk of unhealthy weight gain, an important cardiometabolic risk factor in children. To further our understanding of this relationship, we performed a narrative review using two approaches. First, research examining dietary sugar intake, its associations with cardiometabolic health, impact of genetics on sweet taste perception and intake, and how genetics moderates the association of dietary sugar intake and cardiometabolic risk factors in preschool-aged children 1.5-5 years old is reviewed. Second, methodological considerations for collecting and analyzing dietary intake of sugar, genetic information, and markers of cardiometabolic health among young children are provided. Our key recommendations include the following for researchers: (1) Further longitudinal research on sugar intake and cardiometabolic risk factors is warranted to inform policy decisions and guidelines for healthy eating in preschool-aged children. (2) Consistency in sugar definitions is needed across research studies to aid with comparisons of results. (3) Select dietary collection tools specific to each study's aim and sugar definition(s). (4) Limit subjectivity of dietary assessment tools as this impacts interpretation of study results. (5) Choose non-invasive biomarkers of cardiometabolic disease until the strengths and limitations of available biomarkers in preschool-aged children are clarified. (6) Select approaches that account for the polygenic nature of cardiometabolic disease such as genome risk scores and genome wide association studies to assess how genetics moderates the relationship between dietary sugar intake and cardiometabolic risk. This review highlights potential recommendations that will support a research environment to help inform policy decisions and healthy eating policies to reduce cardiometabolic risk in young children.

Prevalence, clinical features and complications of common forms of Maturity Onset Diabetes of the Young (MODY) seen at a tertiary diabetes centre in south India

BACKGROUND

Maturity Onset Diabetes of the Young (MODY) is a form of monogenic diabetes caused by mutations in single genes, affecting adolescents or young adults. MODY is frequently misdiagnosed as type 1 diabetes (T1). Though several studies from India have reported on the genetic aspects of MODY, the clinical profile, complications and treatments given have not been reported so far, nor compared with T1D and type 2 diabetes (T2D).

AIM

To determine the prevalence, clinical features, and complications of common forms of genetically proven MODY seen at a tertiary diabetes centre in South India and compare them with matched individuals with T1D and T2D.

METHODS

Five hundred and thirty individuals identified as 'possible MODY' based on clinical criteria, underwent genetic testing for MODY. Diagnosis of MODY was confirmed based on pathogenic or likely pathogenic variants found using Genome Aggregation Database (gnomAD) and American College of Medical Genetics (ACMG) criteria. The clinical profile of MODY was compared with individuals with type 1 (T1D) and type 2 (T2D) diabetes, matched for duration of diabetes. Retinopathy was diagnosed by retinal photography; nephropathy by urinary albumin excretion > 30 µg/mg of creatinine and neuropathy by vibration perception threshold > 20 v on biothesiometry.

RESULTS

Fifty-eight patients were confirmed to have MODY (10.9%). HNF1A-MODY (n = 25) was the most common subtype followed by HNF4A-MODY (n = 11), ABCC8-MODY (n = 11), GCK-MODY (n = 6) and HNF1B-MODY (n = 5). For comparison of clinical profile, only the three 'actionable' subtypes - defined as those who may respond to sulphonylureas, namely, HNF1A, HNF4A and ABCC8-MODY, were included. Age at onset of diabetes was lower among HNF4A-MODY and HNF1A-MODY than ABCC8-MODY, T1D and T2D. Prevalence of retinopathy and nephropathy was higher among the three MODY subtypes taken together (n = 47) as compared to T1D (n = 86) and T2D (n = 86).

CONCLUSION

This is one of the first reports of MODY subtypes from India based on ACMG and gnomAD criteria. The high prevalence of retinopathy and nephropathy in MODY points to the need for earlier diagnosis and better control of diabetes in individuals with MODY.

[Diabetes and Pregnancy]

The quality of metabolic control at the beginning of pregnancy already determines the course and outcome of pregnanies with type 1 and type 2 diabetes mellitus. The preconceptional counseling and support provided by experienced teams is more important than modern technical equipment with insulin pumps and sensors for continuous glucose measurement. The incidence of congenital malformations is significantly reduced by a periconceptional HbA1c level < 6.5 % and folic acid supplementation started preconceptionally. To prevent preeclampsia, all women with type 1 and type 2 diabetes mellitus should be offered low-dose ASA, starting before 16 weeks of pregnancy. If the pregnant woman has a BMI < 25 kg/m² and persistently elevated fasting blood glucose levels, a GCK-MODY should be considered. For the diagnosis of asymptomatic gestational diabetes mellitus, all women in Germany with 24 + 0 to 27 + 6 weeks of pregnancy are offered a two-stage screening. Structured follow-up care is required after gestational diabetes mellitus, because these women have an increased risk of developing type 2 diabetes mellitus and cardiovascular complications. Pregnant women with COVID-19 and hyperglycemia have an increased risk of a severe course of the infection, which is further increased by obesity - they are an important target group for vaccination with an mRNA vaccine.

Maturity-onset Diabetes of the Young (MODY) in Pregnancy: A Review

Hyperglycaemia in pregnancy is one of the most common complications of pregnancy and is generally diagnosed as gestational diabetes mellitus (GDM). Nevertheless, clinical symptoms of hyperglycaemia in pregnancy in some cases do not match the clinical manifestations of GDM. It is suspected that 1-2 % of women diagnosed with GDM are misdiagnosed maturity-onset diabetes of the young (MODY). MODY often has a subclinical course; thus, it is challenging for clinicians to aptly diagnose monogenic diabetes in pregnancy. Proper diagnosis is crucial for the effective treatment of hyperglycaemia in pregnancy. Many studies revealed that misdiagnosis of MODY increases the rate of complications for both mother and fetus. This literature review reports the current knowledge regarding diagnosis, treatment, and complications of the most common types of MODY in pregnancy.

GCK-MODY in pregnancy: A pregnant woman with diabetes and a small-for-gestational-age fetus

Glucokinase-maturity-onset diabetes of the young (GCK-MODY) is often misdiagnosed as other forms of diabetes. A 42-year-old pregnant lady with pre-existing diabetes was treated with insulin during first trimester. Fetal growth restriction was noted since mid-second trimester. Genetic testing suggested the diagnosis of GCK-MODY.

The Challenges of Treating Glucokinase MODY during Pregnancy: A Review of Maternal and Fetal Outcomes

Background: The optimal treatment strategy for the follow-up and management of women with glucokinase maturity-onset diabetes of the young (GCK−MODY)during pregnancy remains unknown. Data regarding maternal and fetal outcomes are lacking. Aim: This paper summarizes the existing literature regarding the maternal and fetal outcomes of women with glucokinase MODY to guide future treatment strategy. Methods: A literature search was conducted in Pubmed, Embace, and Cochrane library with citation follow-up using the terms: glucokinase, MODY, diabetes, pregnancy, gestation, and outcomes. We searched for articles with known fetal mutational status. Relevant outcomes included: birthweight, large for gestational age (LGA), small for gestational age (SGA), macrosomia, cesarean delivery (CD), shoulder dystocia, congenital anomalies, miscarriages, preterm births, and long-term outcomes. Results: Fourteen relevant manuscripts were identified describing maternal and fetal outcomes. The percentage of LGA and macrosomia in 102 glucokinase -unaffected offspring (GCK−) was significantly higher than in the glucokinase -affected offspring (GCK+) (44% vs. 10%, p < 0.001 and 22% vs. 2%, p < 0.001, respectively). Among the 173 GCK(+) offspring, only 5% were SGA, which can be expected according to the normal distribution. We observed higher rates of CD and shoulder dystocia in the GCK(−) offspring. Conclusions: GCK(−) offspring have significantly higher birthweights and more birth complications. The optimal treatment strategy to guide management should take into consideration multiple variables other than fetal mutational status.

β-Klotho promotes glycolysis and glucose-stimulated insulin secretion via GP130

Impaired glucose-stimulated insulin secretion (GSIS) is a hallmark of type-2 diabetes. However, cellular signaling machineries that control GSIS remain incompletely understood. Here, we report that β-klotho (KLB), a single-pass transmembrane protein known as a co-receptor for fibroblast growth factor 21 (FGF21), fine tunes GSIS via modulation of glycolysis in pancreatic β-cells independent of the actions of FGF21. β-cell-specific deletion of Klb but not Fgf21 deletion causes defective GSIS and glucose intolerance in mice and defective GSIS in islets of type-2 diabetic mice is mitigated by adenovirus-mediated restoration of KLB. Mechanistically, KLB interacts with and stabilizes the cytokine receptor subunit GP130 by blockage of ubiquitin-dependent lysosomal degradation, thereby facilitating interleukin-6-evoked STAT3-HIF1α signaling, which in turn transactivates a cluster of glycolytic genes for adenosine triphosphate production and GSIS. The defective glycolysis and GSIS in Klb-deficient islets are rescued by adenovirus-mediated replenishment of STAT3 or HIF1α. Thus, KLB functions as a key cell-surface regulator of GSIS by coupling the GP130 receptor signaling to glucose catabolism in β-cells and represents a promising therapeutic target for diabetes.

Pregnancy in Women With Monogenic Diabetes due to Pathogenic Variants of the Glucokinase Gene: Lessons and Challenges

Heterozygous loss-of-function variants of the glucokinase (GCK) gene are responsible for a subtype of maturity-onset diabetes of the young (MODY). GCK-MODY is characterized by a mild hyperglycemia, mainly due to a higher blood glucose threshold for insulin secretion, and an up-regulated glucose counterregulation. GCK-MODY patients are asymptomatic, are not exposed to diabetes long-term complications, and do not require treatment. The diagnosis of GCK-MODY is made on the discovery of hyperglycemia by systematic screening, or by family screening. The situation is peculiar in GCK-MODY women during pregnancy for three reasons: 1. the degree of maternal hyperglycemia is sufficient to induce pregnancy adverse outcomes, as in pregestational or gestational diabetes; 2. the probability that a fetus inherits the maternal mutation is 50% and; 3. fetal insulin secretion is a major stimulus of fetal growth. Consequently, when the fetus has not inherited the maternal mutation, maternal hyperglycemia will trigger increased fetal insulin secretion and growth, with a high risk of macrosomia. By contrast, when the fetus has inherited the maternal mutation, its insulin secretion is set at the same threshold as the mother's, and no fetal growth excess will occur. Thus, treatment of maternal hyperglycemia is necessary only in the former situation, and will lead to a risk of fetal growth restriction in the latter. It has been recommended that the management of diabetes in GCK-MODY pregnant women should be guided by assessment of fetal growth by serial ultrasounds, and institution of insulin therapy when the abdominal circumference is ≥ 75th percentile, considered as a surrogate for the fetal genotype. This strategy has not been validated in women with in GCK-MODY. Recently, the feasibility of non-invasive fetal genotyping has been demonstrated, that will improve the care of these women. Several challenges persist, including the identification of women with GCK-MODY before or early in pregnancy, and the modalities of insulin therapy. Yet, retrospective observational studies have shown that fetal genotype, not maternal treatment with insulin, is the main determinant of fetal growth and of the risk of macrosomia. Thus, further studies are needed to specify the management of GCK-MODY pregnant women during pregnancy.

Monogenic diabetes caused by GCK gene mutation is misdiagnosed as gestational diabetes - A multicenter study in Portugal

AIMS

Monogenic diabetes is an underdiagnosed type of diabetes mellitus, which can be harmful in pregnancy. We aim to estimate the prevalence of diabetes caused by the mutation of the glucokinase gene (GCK-MODY) in pregnant women diagnosed with gestational diabetes mellitus (GDM) and to characterize pregnant women with this suspicion.

METHODS

A multicenter observational study with data prospectively collected from pregnancies with GDM was conducted. Two groups of pregnant women were considered: those with GCK-MODY criteria and those without those criteria.

RESULTS

Of 18421 women with GDM, 3.6% (n = 730) had the GCK-MODY clinical criteria. A prevalence of 1.5% of GCK-MODY is estimated in women with GDM in Portugal, which is higher than in Northern European countries. Suspected GCK-MODY women had statistically higher odds of having neonates below the 25th percentile (OR = 1.23, 95%CI = 1.04-1.46, p = 0.016) and having prediabetes and diabetes in postpartum reclassification (OR = 2.11, 95%CI = 1.55-2.82, p < 0.001 and OR = 5.96, 95%CI = 3.38-10.06, p < 0.001, respectively).

CONCLUSIONS

Higher odds of neonates below the 25th percentile was probably due to excessive insulin treatment in cases where both the mother and the fetus have the mutation. It is essential to consider the diagnosis of GCK-MODY in all women with GDM criteria for better management of diabetes in pregnancy.

Maturity Onset Diabetes of the Young-New Approaches for Disease Modelling

Maturity-onset diabetes of the young (MODY) is a genetically heterogeneous group of monogenic endocrine disorders that is characterised by autosomal dominant inheritance and pancreatic β-cell dysfunction. These patients are commonly misdiagnosed with type 1 or type 2 diabetes, as the clinical symptoms largely overlap. Even though several biomarkers have been tested none of which could be used as single clinical discriminator. The correct diagnosis for individuals with MODY is of utmost importance, as the applied treatment depends on the gene mutation or is subtype-specific. Moreover, in patients with HNF1A-MODY, additional clinical monitoring can be included due to the high incidence of vascular complications observed in these patients. Finally, stratification of MODY patients will enable better and newer treatment options for MODY patients, once the disease pathology for each patient group is better understood. In the current review the clinical characteristics and the known disease-related abnormalities of the most common MODY subtypes are discussed, together with the up-to-date applied diagnostic criteria and treatment options. Additionally, the usage of pluripotent stem cells together with CRISPR/Cas9 gene editing for disease modelling with the possibility to reveal new pathophysiological mechanisms in MODY is discussed.

Tunisian Maturity-Onset Diabetes of the Young: A Short Review and a New Molecular and Clinical Investigation

INTRODUCTION/AIMS

Maturity-Onset Diabetes of the Young (MODY) is a monogenic non-autoimmune diabetes with 14 different genetic forms. MODY-related mutations are rarely found in the Tunisian population. Here, we explored MODY related genes sequences among seventeen unrelated Tunisian probands qualifying the MODY clinical criteria.

MATERIALS AND METHODS

The GCK and HNF1A genes were systematically analyzed by direct sequencing in all probands. Then, clinical exome sequencing of 4,813 genes was performed on three unrelated patients. Among them, 130 genes have been reported to be involved in the regulation of glucose metabolism, β-cell development, differentiation and function. All identified variants were analyzed according to their frequencies in the GnomAD database and validated by direct sequencing.

RESULTS

We identified the previously reported GCK mutation (rs1085307455) in one patient. The clinical features of the MODY2 proband were similar to previous reports. In this study, we revealed rare and novel alterations in GCK (rs780806456) and ABCC8 (rs201499958) genes with uncertain significance. We also found two likely benign alterations in HNF1A (rs1800574) and KLF11 (rs35927125) genes with minor allele frequencies similar to those depicted in public databases. No pathogenic variants have been identified through clinical exome analysis.

CONCLUSIONS

The most appropriate patients were selected, following a strict clinical screening approach, for genetic testing. However, the known MODY1-13 genes could not explain most of the Tunisian MODY cases, suggesting the involvement of unidentified genes in the majority of Tunisian affected families.

The epidemiology, molecular pathogenesis, diagnosis, and treatment of maturity-onset diabetes of the young (MODY)

Background

The most common type of monogenic diabetes is maturity-onset diabetes of the young (MODY), a clinically and genetically heterogeneous group of endocrine disorders that affect 1–5% of all patients with diabetes mellitus. MODY is characterized by autosomal dominant inheritance but de novo mutations have been reported. Clinical features of MODY include young-onset hyperglycemia, evidence of residual pancreatic function, and lack of beta cell autoimmunity or insulin resistance. Glucose-lowering medications are the main treatment options for MODY. The growing recognition of the clinical and public health significance of MODY by clinicians, researchers, and governments may lead to improved screening and diagnostic practices. Consequently, this review article aims to discuss the epidemiology, pathogenesis, diagnosis, and treatment of MODY based on relevant literature published from 1975 to 2020.

Main body

The estimated prevalence of MODY from European cohorts is 1 per 10,000 in adults and 1 per 23,000 in children. Since little is known about the prevalence of MODY in African, Asian, South American, and Middle Eastern populations, further research in non-European cohorts is needed to help elucidate MODY’s exact prevalence. Currently, 14 distinct subtypes of MODY can be diagnosed through clinical assessment and genetic analysis. Various genetic mutations and disease mechanisms contribute to the pathogenesis of MODY. Management of MODY is subtype-specific and includes diet, oral antidiabetic drugs, or insulin.

Conclusions

Incidence and prevalence estimates for MODY are derived from epidemiologic studies of young people with diabetes who live in Europe, Australia, and North America. Mechanisms involved in the pathogenesis of MODY include defective transcriptional regulation, abnormal metabolic enzymes, protein misfolding, dysfunctional ion channels, or impaired signal transduction. Clinicians should understand the epidemiology and pathogenesis of MODY because such knowledge is crucial for accurate diagnosis, individualized patient management, and screening of family members.

Maternal or Paternal Diabetes and Its Crucial Role in Offspring Birth Weight and MODY Diagnosis

Maturity-onset diabetes of the young (MODY) represents a heterogenous group of monogenic autosomal dominant diseases, which accounts for 1-2% of all diabetes cases. Pregnancy represents a crucial time to diagnose MODY forms due to the 50% risk of inheritance in offspring of affected subjects and the potential implications on adequate fetal weight. Not only a history of maternal diabetes may affect the birth weight of offspring, paternal diabetes should also be taken into consideration for a correct pathogenetic diagnosis. The crucial role of maternal and paternal diabetes inheritance patterns and the impact of this inherited mutation on birthweight and the MODY diagnosis was discussed.

Identification of MODY among patients screened for gestational diabetes: a clinician's guide

PURPOSE

Screening of gestational diabetes/GDM (although different in different countries) represents a standard procedure allowing to identify women with pregnancy-associated diabetes. Some of the women with GDM (up to 5%) may, however, suffer from previously undiagnosed MODY (Maturity-Onset Diabetes of the Young). Currently, no international or local guidelines focused on the identification of MODY among GDM exist. Thus, the aim of this manuscript is to propose a clear guide for clinicians on how to detect MODY among pregnant women with gestational diabetes.

METHODS

Based on the available literature about diagnosis (in general population) of MODY and management of MODY (both, in general population and in pregnant women), we propose a clear clinical guide on how to diagnose and manage MODY in pregnancy.

RESULTS

The manuscript suggests a feasible clinical approach how to recognize MODY among patients with GDM and how to manage pregnancy of women with three most common MODY subtypes.

CONCLUSION

A correct classification of diabetes is, nonetheless, essential, particularly in case of MODY, as the management of pregnant women with MODY is different and the correct diagnosis of MODY enables individualized treatment with regard to optimal pregnancy outcomes.

Molecular Modelling of Islet β-Cell Adaptation to Inflammation in Pregnancy and Gestational Diabetes Mellitus

Gestational diabetes mellitus (GDM), a metabolic disease that develops with the increase in insulin resistance during late pregnancy, is currently one of the most common complications affecting pregnancy. The polygenic nature of GDM, together with the interplay between different genetic variants with nutritional and environmental factors has hindered the full understanding of the etiology of this disease. However, an important genetic overlap has been found with type 2 diabetes mellitus (T2DM) and, as in the case of T2DM, most of the identified loci are associated with β-cell function. Early detection of GDM and adequate interventions to control the maternal glycemia are necessary to avoid the adverse outcomes for both the mother and the offspring. The in utero exposure to the diabetic milieu predispose these children for future diseases, among them T2DM, originating a vicious circle implicated in the increased prevalence of both GDM and T2DM. The involvement of inflammatory processes in the development of GDM highlights the importance of pancreatic β-cell factors able to favor the adaptation processes required during gestation, concomitantly with the protection of the islets from an inflammatory milieu. In this regard, two members of the Pax family of transcription factors, PAX4 and PAX8, together with the chromatin remodeler factor HMG20A, have gained great relevance due to their involvement in β-cell mass adaptation together with their anti-inflammatory properties. Mutations in these factors have been associated with GDM, highlighting these as novel candidates for genetic screening analysis in the identification of women at risk of developing GDM.