Management and Outcomes of Maturity-Onset Diabetes of the Young in Pregnancy

Pregnancy outcome with maternal HNF1B gene mutations and 17q12 deletions

There is an increasing body of literature regarding monogenic diabetes, particularly the more common forms of glucokinase and HNF1-alpha mutations (MODY2 and MODY3). There is relatively little published literature regarding rarer mutations. HNF1-beta mutations and 17q12 deletions may be associated with a broad range of organ dysfunction, renal disease and diabetes in particular resulting in high-risk pregnancies. This manuscript describes pregnancy outcomes in a woman with an HNF1-beta mutation and 2 women with an HNF1B/17q12 deletion and reviews the previously published literature. It highlights the significant rate of adverse maternal and fetal outcomes, and the maternal features suggestive of the diagnosis which should be considered in preconception counselling.

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.

Predominant genetic mutations leading to or predisposing diabetes progress: A Review

Diabetes mellitus (DM) arises following poor capacity to generate or secrete insulin or insulin resistance; hence insulin production impairment creates the illness. Individuals can control their weight, impulsivity, blood pressure, and blood lipids at the commencement of the disease. A single genetic mutation affects nearly 3% of people with diabetes. Surprisingly, beta cell function is regulated by more than 20 genes. Benefits of genetic diagnosis include improved therapy, better prediction of illness prognosis and progression, genetic counseling, and possibly prevention. Alpha HNF1 mutations in the early stages may respond to the regimen. Still, most patients need it because they control their blood glucose and will be subject to microvascular or macrovascular complications. In cases where insulin does not control sugar, using low-dose sulfonylureas would be beneficial and lower four times the glucose metabolism of metformin. These patients are susceptible to sulfonylureas and may be treated for years in case of no blood glucose attack complications. The drug will start at one-fourth of the adult dose: MODY1. It is caused by a mutation in the alpha-HNF 4 gene and is relatively uncommon. The same is true, but the threshold for renal excretion is not low, and the incidence of upward alpha-HNF 4 mutations in cases where there is a robust clinical panel for alpha HNF 1 but not confirmed by genetic sequencing should be considered. The disease is also susceptible to sulfonylureas: MODY4 with a mutation in the MODY6 gene, IPF1, with a mutation in MODY7, NeuroD1 is characterized by a carboxy sterilise mutation, which is not common: MODY2. In children and adolescents, an increment in fasting blood glucose of 100 to 150 mg/dl is not typical. The incidence of this condition is usually considered to be type 1 or 2 diabetes, but a large percentage of the above patients are heterozygote individuals, the glucokinase mutations. Specific mutations, including those rare variants in WFS1 and ABCC8 genes, insulin receptor (IR), fructose 6-phosphate aminotransferase (GFPT2), and nitric oxide synthase (eNOS), as well as mouse pancreatic β‐cell lines (Min6 and SJ cells), showed that the HDAC4 variant (p. His227Arg) had been directly linked with T2DM. Keywords: type-2 diabetes, genetic mutations, risk factors

Report of Prolonged Neonatal Hypoglycemia in Three Infants of Mothers With Variants in HNF1A

Background/Objective

Genetic variants in hepatic nuclear factor 1α (HNF1A) cause maturity-onset diabetes of the young (MODY). We sought to examine whether HNF1A MODY variants also cause neonatal hypoglycemia.

Case Report

We present 3 infants with variants in HNF1A shared with their mothers. The infants experienced neonatal hypoglycemia, 2 extending beyond 1 year and the third resolving by 28 days, and all were large for gestational age (birth weights of >99th percentile). In 2 cases, genetic testing for neonatal hypoglycemia revealed pathogenic variants in HNF1A; 1 mother was previously diagnosed with HNF1A MODY, and the other's genetic testing and ultimate MODY diagnosis were prompted by her child's hypoglycemia workup. In the third case, the infant's persistent hypoglycemia prompted genetic testing, revealing an HNF1A variant of uncertain significance, which was then identified in the mother.

Discussion

Genetic variants causing HNF1A MODY have not been definitively linked to neonatal hypoglycemia or fetal overgrowth in utero. MODY caused by HNF1A is clinically similar to that caused by HNF4A, for which a causal relationship with neonatal hypoglycemia is more certain. Case reports have previously implicated variants in HNF1A in congenital hyperinsulinism; however, these cases have generally not been in families with MODY. The cases presented here suggest that HNF1A variants causing MODY may also cause neonatal hypoglycemia.

Conclusion

Although confounding factors make the assessment of neonatal hypoglycemia challenging, these cases offer potential support for single genetic variants in HNF1A causing both MODY and neonatal hypoglycemia, with associated fetal overgrowth in utero.

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.

The Application of Next Generation Sequencing Maturity Onset Diabetes of the Young Gene Panel in Turkish Patients from Trakya Region

OBJECTIVE

The aim of this study was to investigate the molecular basis of maturity-onset diabetes of the young (MODY) by targeted-gene sequencing of 20 genes related to monogenic diabetes, estimate the frequency and describe the clinical characteristics of monogenic diabetes and MODY in the Trakya Region of Turkey.

METHODS

A panel of 20 monogenic diabetes related genes were screened in 61 cases. Illumina NextSeq550 system was used for sequencing. Pathogenicity of the variants were assessed by bioinformatics prediction software programs and segregation analyses.

RESULTS

In 29 (47.5%) cases, 31 pathogenic/likely pathogenic variants in the GCK, ABCC8, KCNJ11, HNF1A, HNF4A genes and in 11 (18%) cases, 14 variants of uncertain significance (VUS) in the GCK, RFX6, CEL, PDX1, KCNJ11, HNF1A, G6PC2, GLIS3 and KLF11 genes were identified. There were six different pathogenic/likely pathogenic variants and six different VUS which were novel.

CONCLUSION

This is the first study including molecular studies of twenty monogenic diabetes genes in Turkish cases in the Trakya Region. The results showed that pathogenic variants in the GCK gene are the leading cause of MODY in our population. A high frequency of novel variants (32.4%-12/37) in the current study, suggests that multiple gene analysis provides accurate genetic diagnosis in MODY.

Monogenic Diabetes: From Genetic Insights to Population-Based Precision in Care. Reflections From a Diabetes Care Editors' Expert Forum

Individualization of therapy based on a person's specific type of diabetes is one key element of a "precision medicine" approach to diabetes care. However, applying such an approach remains difficult because of barriers such as disease heterogeneity, difficulties in accurately diagnosing different types of diabetes, multiple genetic influences, incomplete understanding of pathophysiology, limitations of current therapies, and environmental, social, and psychological factors. Monogenic diabetes, for which single gene mutations are causal, is the category most suited to a precision approach. The pathophysiological mechanisms of monogenic diabetes are understood better than those of any other form of diabetes. Thus, this category offers the advantage of accurate diagnosis of nonoverlapping etiological subgroups for which specific interventions can be applied. Although representing a small proportion of all diabetes cases, monogenic forms present an opportunity to demonstrate the feasibility of precision medicine strategies. In June 2019, the editors of Diabetes Care convened a panel of experts to discuss this opportunity. This article summarizes the major themes that arose at that forum. It presents an overview of the common causes of monogenic diabetes, describes some challenges in identifying and treating these disorders, and reports experience with various approaches to screening, diagnosis, and management. This article complements a larger American Diabetes Association effort supporting implementation of precision medicine for monogenic diabetes, which could serve as a platform for a broader initiative to apply more precise tactics to treating the more common forms of diabetes.

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.