Maturity-onset diabetes of the young (MODY): an update

A Review of Functional Characterization of Single Amino Acid Change Mutations in HNF Transcription Factors in MODY Pathogenesis

Mutations in HNF transcription factor genes cause the most common subtypes of maturity-onset of diabetes of youth (MODY), a monogenic form of diabetes mellitus. Mutations in the HNF1-α, HNF4-α, and HNF1-β genes are primarily considered as the cause of MODY3, MODY1, and MODY5 subtypes, respectively. Although patients with different subtypes display similar symptoms, they may develop distinct diabetes-related complications and require different treatments depending on the type of the mutation. Genetic analysis of MODY patients revealed more than 400 missense/nonsense mutations in HNF1-α, HNF4-α, and HNF1-β genes, however only a small portion of them are functionally characterized. Evaluation of nonsense mutations are more direct as they lead to premature stop codons and mostly in mRNA decay or nonfunctional truncated proteins. However, interpretation of the single amino acid change (missense) mutation is not such definite, as effect of the variant may vary depending on the location and also the substituted amino acid. Mutations with benign effect on the protein function may not be the pathologic variant and further genetic testing may be required. Here, we discuss the functional characterization analysis of single amino acid change mutations identified in HNF1-α, HNF4-α, and HNF1-β genes and evaluate their roles in MODY pathogenesis. This review will contribute to comprehend HNF nuclear family-related molecular mechanisms and to develop more accurate diagnosis and treatment based on correct evaluation of pathologic effects of the variants.

Insights into the etiology and physiopathology of MODY5/HNF1B pancreatic phenotype with a mouse model of the human disease

Maturity-onset diabetes of the young type 5 (MODY5) is due to heterozygous mutations or deletion of HNF1B. No mouse models are currently available to recapitulate the human MODY5 disease. Here, we investigate the pancreatic phenotype of a unique MODY5 mouse model generated by heterozygous insertion of a human HNF1B splicing mutation at the intron-2 splice donor site in the mouse genome. This Hnf1bsp2/+ model generated with targeted mutation of Hnf1b mimicking the c.544+1G>T (T) mutation identified in humans, results in alternative transcripts and a 38% decrease of native Hnf1b transcript levels. As a clinical feature of MODY5 patients, the hypomorphic mouse model Hnf1bsp2/+ displays glucose intolerance. Whereas Hnf1bsp2/+ isolated islets showed no altered insulin secretion, we found a 65% decrease in pancreatic insulin content associated with a 30% decrease in total large islet volume and a 20% decrease in total β-cell volume. These defects were associated with a 30% decrease in expression of the pro-endocrine gene Neurog3 that we previously identified as a direct target of Hnf1b, showing a developmental etiology. As another clinical feature of MODY5 patients, the Hnf1bsp2/+ pancreases display exocrine dysfunction with hypoplasia. We observed chronic pancreatitis with loss of acinar cells, acinar-to-ductal metaplasia, and lipomatosis, with upregulation of signaling pathways and impaired acinar cell regeneration. This was associated with ductal cell deficiency characterized by shortened primary cilia. Importantly, the Hnf1bsp2/+ mouse model reproduces the pancreatic features of the human MODY5/HNF1B disease, providing a unique in vivo tool for molecular studies of the endocrine and exocrine defects and to advance basic and translational research. © 2021 The Authors. The Journal of Pathology published by John Wiley & Sons, Ltd. on behalf of The Pathological Society of Great Britain and Ireland.

Clinical and laboratory clues of maturity-onset diabetes of the young and determination of association with molecular diagnosis

BACKGROUND/AIM

Maturity-onset diabetes of the young (MODY) is often misdiagnosed as other types of diabetes because it is overlooked due to atypical clinical presentations. This study aims to reveal the clinical and laboratory clues and examine their compatibility with MODY genotypes.

METHODS

Participants consisted of 230 children with atypical presentations for type1(T1DM) and type2 diabetes mellitus (T2DM). MODY-causing mutations were screened in the following genes:GCK-HNF1A-HNF4A-HNF1B-PDX1-NEUROD1-KLF11-CEL-PAX4-INS-BLK. Clinical and laboratory features were compared between children with MODY and children without MODY.

RESULTS

The most common reasons for MODY screening were as follows (n/%):low daily dose of insulin (DDI) requirement (122/53%), absence of beta-cell antibodies(58/25.3%), coincidental hyperglycemia(26/11.3%), family history of diabetes (12/5.2%), hypoglycemia/hyperglycemia episodes(7/3%), hyperglycemia related to steroids(3/1.4%) and renal glycosuria(2/0.8%). The markers with the most likelihood to distinguish MODY from T1DM were determined as follows: measurable C-peptide in follow-up, family history of early-onset diabetes and low DDI requirement (odds ratio:12.55, 5.53 and 3.43, respectively). The distribution of the most common causative genes in children with MODY(n = 24) is as follows (n/%):GCK(15/62.5%), HNF4A(7/29.1%), HNF1A(1/9.2%) and PDX1(1/9.2%).All children(n = 12) with GCK-MODY(MODY2) were screened for low DDI requirement, while beta-cell negativity was more common in HNF4A-MODY(MODY1).

CONCLUSION

The study shows that measurable C-peptide in follow-up, family history of early-onset diabetes, and low DDI are still remarkable clues to predict MODY in children with misdiagnosed T1DM. In addition, the most common mutations were found in the GCK and HNF4A genes. Among children misdiagnosed with T1DM, a low DDI requirement was found more frequently in MODY2, whereas beta-cell antibody negativity was more common in MODY1.

The Contribution of Transcriptional Coregulators in the Maintenance of β-cell Function and Identity

Islet β-cell dysfunction that leads to impaired insulin secretion is a principal source of pathology of diabetes. In type 2 diabetes, this breakdown in β-cell health is associated with compromised islet-enriched transcription factor (TF) activity that disrupts gene expression programs essential for cell function and identity. TF activity is modulated by recruited coregulators that govern activation and/or repression of target gene expression, thereby providing a supporting layer of control. To date, more than 350 coregulators have been discovered that coordinate nucleosome rearrangements, modify histones, and physically bridge general transcriptional machinery to recruited TFs; however, relatively few have been attributed to β-cell function. Here, we will describe recent findings on those coregulators with direct roles in maintaining islet β-cell health and identity and discuss how disruption of coregulator activity is associated with diabetes pathogenesis.

HNF1A-MODY Mutations in Nuclear Localization Signal Impair HNF1A-Import Receptor KPNA6 Interactions

Mutations in hepatocyte nuclear factor (HNF)1A gene cause the most common form of Maturity-onset diabetes of the young (MODY), a monogenic subtype of diabetes mellitus. Functional characterization of mutant proteins reveals that mutations may disrupt DNA binding capacity, transactivation ability and nuclear localization of HNF1A depending on the position of the mutation. Previously identified Arg271Trp and Ser345Tyr mutations in HNF1A were found to be defective in nuclear localization. Arg271 residue resides in a region similar to classical nuclear localization signal (NLS) motif, while Ser345 does not. Importin α family members recognize NLS motifs on cargo proteins and subsequently translocate them into nucleus. Here, we first investigated the nuclear localization mechanism of wild type HNF1A protein. For this purpose, we analyzed the interaction of HNF1A with three mouse homolog importin α proteins (KPNA2, KPNA4 and KPNA6) by co-immunoprecipitation assay and molecular docking simulation. Hereby, KPNA6 was identified as the main import receptor, which is responsible for the transport of HNF1A into the nucleus. Immunolocalization studies in mouse pancreatic cells (Min6) also confirmed the co-localization of HNF1A and KPNA6 in the cytoplasm. Secondly, the interaction between KPNA6 and mutant HNF1A proteins (Arg271Trp and Ser345Tyr) was assessed. Co-immunoprecipitation studies revealed a reduced interaction compared to wild type HNF1A. Our study demonstrated for the first time that HNF1A transcription factor is recognized and transported by importin/karyopherin import family, and mutations in NLS motifs may disrupt the interaction leading to nuclear localization abnormalities and MODY phenotype.

Clinical features, complications and treatment of rarer forms of maturity-onset diabetes of the young (MODY) - A review

Maturity onset diabetes of the young (MODY) is the most common form of monogenic diabetes and is currently believed to have 14 subtypes. While much is known about the common subtypes of MODY (MODY-1, 2, 3 and 5) little is known about its rare subtypes (MODY4, 6-14). With the advent of next-generation sequencing (NGS) there are several reports of the rarer subtypes of MODY emerging from across the world. Therefore, a greater understanding on these rarer subtypes is needed. A search strategy was created, and common databases were searched, and 51 articles finally selected. INS-(MODY10) and ABCC8-(MODY12) mutations were reported in relatively large numbers compared to the other rare subtypes. The clinical characteristics of the rare MODY subtypes exhibited heterogeneity between families reported with the same mutation. Obesity and diabetic ketoacidosis (DKA) were also reported among rarer MODY subtypes which presents as a challenge as these are not part of the original description of MODY by Tattersal and Fajans. The treatment modalities of the rarer subtypes included oral drugs, predominantly sulfonylureas, insulin but also diet alone. Newer drugs like DPP-4 and SGLT2 inhibitors have also been tried as new modes of treatment. The microvascular and macrovascular complications among the patients with various MODY subtypes are less commonly reported. Recently, there is a view that not all the 14 forms of 'MODY' are true MODY and the very existence of some of these rarer subtypes as MODY has been questioned. This scoping review aims to report on the clinical characteristics, treatment and complications of the rarer MODY subtypes published in the literature.

Protein Glycosylation in Diabetes

Diabetes mellitus is a group of metabolic disorders characterized by the presence of hyperglycaemia. Due to its high prevalence and substantial heterogeneity, many studies have been investigating markers that could identify predisposition for the disease development, differentiate between the various subtypes, establish early diagnosis, predict complications or represent novel therapeutic targets. N-glycans, complex oligosaccharide molecules covalently linked to proteins, emerged as potential markers and functional effectors of various diabetes subtypes, appearing to have the capacity to meet these requirements. For instance, it has been shown that N-glycome changes in patients with type 2 diabetes and that N-glycans can even identify individuals with an increased risk for its development. Moreover, genome-wide association studies identified glycosyltransferase genes as candidate causal genes for both type 1 and type 2 diabetes. N-glycans have also been suggested to have a major role in preventing the impairment of glucose-stimulated insulin secretion by modulating cell surface expression of glucose transporters. In this chapter we aimed to describe four major diabetes subtypes: type 1, type 2, gestational and monogenic diabetes, giving an overview of suggested role for N-glycosylation in their development, diagnosis and management.

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.

Challenges in the diagnosis of diabetes type in pediatrics

The incidence of diabetes, both type 1 and type 2, is increasing. Health outcomes in pediatric diabetes are currently poor, with trends indicating that they are worsening. Minority racial/ethnic groups are disproportionately affected by suboptimal glucose control and have a higher risk of acute and chronic complications of diabetes. Correct clinical management starts with timely and accurate classification of diabetes, but in children this is becoming increasingly challenging due to high prevalence of obesity and shifting demographic composition. The growing obesity epidemic complicates classification by obesity's effects on diabetes. Since the prevalence and clinical characteristics of diabetes vary among racial/ethnic groups, migration between countries leads to changes in the distribution of diabetes types in a certain geographical area, challenging the clinician's ability to classify diabetes. These challenges must be addressed to correctly classify diabetes and establish an appropriate treatment strategy early in the course of disease for all. This may be the first step in improving diabetes outcomes across racial/ethnic groups. This review will discuss the pitfalls in the current diabetes classification scheme that is leading to increasing overlap between diabetes types and heterogeneity within each type. It will also present proposed alternative classification schemes and approaches to understanding diabetes type that may improve the timely and accurate classification of pediatric diabetes type.

Chemical Starting Matter for HNF4α Ligand Discovery and Chemogenomics

Hepatocyte nuclear factor 4α (HNF4α) is a ligand-sensing transcription factor and presents as a potential drug target in metabolic diseases and cancer. In humans, mutations in the HNF4α gene cause maturity-onset diabetes of the young (MODY), and the elevated activity of this protein has been associated with gastrointestinal cancers. Despite the high therapeutic potential, available ligands and structure-activity relationship knowledge for this nuclear receptor are scarce. Here, we disclose a chemically diverse collection of orthogonally validated fragment-like activators as well as inverse agonists, which modulate HNF4α activity in a low micromolar range. These compounds demonstrate the druggability of HNF4α and thus provide a starting point for medicinal chemistry as well as an early tool for chemogenomics.

Functional Genomics in Pancreatic β Cells: Recent Advances in Gene Deletion and Genome Editing Technologies for Diabetes Research

The inheritance of variants that lead to coding changes in, or the mis-expression of, genes critical to pancreatic beta cell function can lead to alterations in insulin secretion and increase the risk of both type 1 and type 2 diabetes. Recently developed clustered regularly interspaced short palindromic repeats (CRISPR/Cas9) gene editing tools provide a powerful means of understanding the impact of identified variants on cell function, growth, and survival and might ultimately provide a means, most likely after the transplantation of genetically "corrected" cells, of treating the disease. Here, we review some of the disease-associated genes and variants whose roles have been probed up to now. Next, we survey recent exciting developments in CRISPR/Cas9 technology and their possible exploitation for β cell functional genomics. Finally, we will provide a perspective as to how CRISPR/Cas9 technology may find clinical application in patients with diabetes.

Molecular Basis for Autosomal-Dominant Renal Fanconi Syndrome Caused by HNF4A

HNF4A is a nuclear hormone receptor that binds DNA as an obligate homodimer. While all known human heterozygous mutations are associated with the autosomal-dominant diabetes form MODY1, one particular mutation (p.R85W) in the DNA-binding domain (DBD) causes additional renal Fanconi syndrome (FRTS). Here, we find that expression of the conserved fly ortholog dHNF4 harboring the FRTS mutation in Drosophila nephrocytes caused nuclear depletion and cytosolic aggregation of a wild-type dHNF4 reporter protein. While the nuclear depletion led to mitochondrial defects and lipid droplet accumulation, the cytosolic aggregates triggered the expansion of the endoplasmic reticulum (ER), autophagy, and eventually cell death. The latter effects could be fully rescued by preventing nuclear export through interfering with serine phosphorylation in the DBD. Our data describe a genomic and a non-genomic mechanism for FRTS in HNF4A-associated MODY1 with important implications for the renal proximal tubule and the regulation of other nuclear hormone receptors.

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HNF4 controls lipid metabolism in Drosophila nephrocytes

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The kidney disease mutation R85W shows dominant-negative effects in nephrocytes

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Dephosphorylation at S87 prevents the dominant-negative effects

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R85W mutation causes mitochondrial dysfunction in reprogrammed renal epithelial cells

Genetic Risk Score in Diabetes Associated With Chronic Pancreatitis Versus Type 2 Diabetes Mellitus

Diabetes mellitus (DM) is a complication of chronic pancreatitis (CP). Whether pancreatogenic diabetes associated with CP-DM represents a discrete pathophysiologic entity from type 2 DM (T2DM) remains uncertain. Addressing this question is needed for development of specific measures to manage CP-DM. We approached this question from a unique standpoint, hypothesizing that if CP-DM and T2DM are separate disorders, they should be genetically distinct. To test this hypothesis, we sought to determine whether a genetic risk score (GRS) based on validated single nucleotide polymorphisms for T2DM could distinguish between groups with CP-DM and T2DM.

Maturity Onset Diabetes of the Young and Generalized Stage III Grade C Periodontitis: A Case Report

INTRODUCTION

Maturity onset diabetes of the young (MODY) is a rare form of diabetes mellitus resulting from single nucleotide polymorphisms. There is a lack of evidence describing their periodontal condition and the management of these patients. The objective of this case report is to present the 6-month outcomes following non-surgical periodontal treatment of a patient diagnosed with MODY 5, the Renal Cyst and Diabetes Syndrome.

CASE PRESENTATION

This case report describes the periodontal presentation and non-surgical management of a 21-year-old patient, diagnosed with hyperglycemia (HbA1c >14%) and stage 4 chronic kidney disease. She presented with generalized severe chronic periodontitis and multiple periodontal abscesses. She was treated with quadrant debridement with adjunctive systemic amoxicillin and metronidazole and 0.2% chlorhexidine mouth rinse. Significant improvement was observed after treatment, remaining stable 6-month post-treatment, with only two sites with probing depths ≥5 mm. This was consistent with a reduction of the periodontal inflamed surface area from 3165 to 500 mm² . HbA1c was also reduced to 8.7% 6 months after treatment.

CONCLUSIONS

MODY patients presenting with periodontitis can be successfully treated non-surgically, concurrent with diabetic management.

The challenges of diagnosing diabetes in childhood

Diabetes is one of the most prevalent diseases worldwide, whereby type 1 diabetes mellitus (T1DM) alone involves nearly 15 million patients. Although T1DM and type 2 diabetes mellitus (T2DM) are the most common types, there are other forms of diabetes which may remain often under-diagnosed, or that can be misdiagnosed as being T1DM or T2DM. After an initial diagnostic step, the differential diagnosis among T1DM, T2DM, Maturity-Onset Diabetes of the Young (MODY) and others forms has important implication for both therapeutic and behavioral decisions. Although the criteria used for diagnosing diabetes mellitus are well defined by the guidelines of the American Diabetes Association (ADA), no clear indications are provided on the optimal approach to be followed for classifying diabetes, especially in children. In this circumstance, both routine and genetic blood test may play a pivotal role. Therefore, the purpose of this article is to provide, through a narrative literature review, some elements that may aid accurate diagnosis and classification of diabetes in children and young people.

Molecular Genetic Study in a Cohort of Iranian Families Suspected to Maturity-Onset Diabetes of the Young, Reveals a Recurrent Mutation and a High-Risk Variant in the CEL Gene

Background

Diabetes mellitus (DM) is a group of metabolic disorders in the body, accompanied with increasing blood sugar levels. Diabetes is classified into three groups: Type 1 DM (T1DM), Type 2 DM (T2DM), and monogenic diabetes. Maturity-onset diabetes of the young (MODY) is a monogenic diabetes that is frequently mistaken for T1D or T2D. The aim of this study was to diagnose MODY and its subtype frequency in a diabetic population in Iran.

Materials and Methods

In this study among ten diabetic families that were highly suspected to MODY by nongenetic biomarkers and without any pathogenic mutation in GCK and HNF1A genes, two patients from two unrelated families were examined via whole-exome sequencing (WES) in order to detect the causative gene of diabetes. Co-segregation analysis of the identified variant was performed using Sanger sequencing.

Results

In this study, no pathogenic variant was found in GCK and HNF1A genes (MODY2 and MODY3), while these two types of MODY were introduced as the most frequent in other studies. By using WES, a pathogenic variant (p.I488T) was found in one of the patients in CEL gene causing MODY8 that its frequency is very rare in other studied populations. A high-risk variant associated with diabetes was found in another patient.

Conclusion

WES was applied in this study to reveal the cause of MODY in 1 family. This pathogenic mutation was previously reported as a disease causing mutation.

The Roles of Long Noncoding RNAs HNF1α-AS1 and HNF4α-AS1 in Drug Metabolism and Human Diseases

Long noncoding RNAs (lncRNAs) are RNAs with a length of over 200 nucleotides that do not have protein-coding abilities. Recent studies suggest that lncRNAs are highly involved in physiological functions and diseases. lncRNAs HNF1α-AS1 and HNF4α-AS1 are transcripts of lncRNA genes HNF1α-AS1 and HNF4α-AS1, which are antisense lncRNA genes located in the neighborhood regions of the transcription factor (TF) genes HNF1α and HNF4α, respectively. HNF1α-AS1 and HNF4α-AS1 have been reported to be involved in several important functions in human physiological activities and diseases. In the liver, HNF1α-AS1 and HNF4α-AS1 regulate the expression and function of several drug-metabolizing cytochrome P450 (P450) enzymes, which also further impact P450-mediated drug metabolism and drug toxicity. In addition, HNF1α-AS1 and HNF4α-AS1 also play important roles in the tumorigenesis, progression, invasion, and treatment outcome of several cancers. Through interacting with different molecules, including miRNAs and proteins, HNF1α-AS1 and HNF4α-AS1 can regulate their target genes in several different mechanisms including miRNA sponge, decoy, or scaffold. The purpose of the current review is to summarize the identified functions and mechanisms of HNF1α-AS1 and HNF4α-AS1 and to discuss the future directions of research of these two lncRNAs.

Simplifying Detection of Copy-Number Variations in Maturity-Onset Diabetes of the Young

OBJECTIVES

Copy-number variations (CNVs) are large-scale deletions or duplications of DNA that have required specialized detection methods, such as microarray-based genomic hybridization or multiplex ligation probe amplification. However, recent advances in bioinformatics have made it possible to detect CNVs from next-generation DNA sequencing (NGS) data. Maturity-onset diabetes of the young (MODY) 5 is a subtype of autosomal-dominant diabetes that is often caused by heterozygous deletions involving the HNF1B gene on chromosome 17q12. We evaluated the utility of bioinformatic processing of raw NGS data to detect chromosome 17q12 deletions in MODY5 patients.

METHODS

NGS data from 57 patients clinically suspected to have MODY but who were negative for pathogenic mutations using a targeted panel were re-examined using a CNV calling tool (CNV Caller, VarSeq version 1.4.3). Potential CNVs for MODY5 were then confirmed using whole-exome sequencing, cytogenetic analysis and breakpoint analysis when possible.

RESULTS

Whole-gene deletions in HNF1B, ranging from 1.46 to 1.85 million basepairs in size, were detected in 3 individuals with features of MODY5. These were confirmed by independent methods to be part of a more extensive 17q12 deletion syndrome. Two additional patients carrying a 17q12 deletion were subsequently diagnosed using this method.

CONCLUSIONS

Large-scale deletions are the most common cause of MODY5 and can be detected directly from NGS data, without the need for additional methods.

Beta cell function and insulin sensitivity in obese youth with maturity onset diabetes of youth mutations vs type 2 diabetes in TODAY: Longitudinal observations and glycemic failure

OBJECTIVE

In treatment options for type 2 diabetes in adolescents and youth (TODAY), 4.5% of obese youth clinically diagnosed with type 2 diabetes (T2D) had genetic variants consistent with maturity onset diabetes of youth (MODY) diagnosis. The course of IS and β-cell function in obese youth with MODY remains unknown. In this secondary analysis, we examined IS and β-cell function in MODY vs. non-MODY obese youth at randomization and over time.

METHODS

Genetic data in TODAY included 426 non-MODY (T2D) and 22 MODY youth (7 glucokinase MODY mutation positive [GCK-MODY], 12 hepatocyte nuclear factor MODY mutation positive [HNF-MODY], 2 Insulin gene mutation [insulin (INS)-MODY], and 1 Kruppel-like factor 11 [KLF11-MODY]). Oral glucose tolerance test (OGTT)-derived IS, C-peptide index, and β-cell function relative to IS oral disposition index (oDI) was measured at randomization, and over 24 months in addition to total and high-molecular-weight adiponectin (HMWA).

RESULTS

At randomization, IS, total adiponectin, and HMWA were significantly higher in the two MODY groups than in non-MODY. β-cell function measured by C-peptide oDI was 3-fold higher in GCK-MODY than in HNF-MODY and 1.5-fold higher than non-MODY (P for both <.05). Glycemic failure rate was 75.0% in HNF-MODY, 46.9% in non-MODY, and zero in GCK-MODY youth. While the changes in IS and oDI were not different among the three groups in the first 6 months, IS improved from 6 to 24 months in HNF-MODY vs GCK-MODY youth.

CONCLUSIONS

In TODAY, β-cell function at randomization was worse in obese HNF-MODY youth compared with GCK-MODY youth, while insulin sensitivity was worse in non-MODY compared with the other two MODY groups. Over time, IS showed the greatest improvement in HNF-MODY youth. This raises the possibility that TODAY therapeutic modalities of insulin sensitization in these obese HNF-MODY youth may have played a beneficial role.

Expression, Epigenetic, and Genetic Changes of HNF1B in Colorectal Lesions: an Analysis of 145 Cases

Hepatocyte nuclear factor 1 beta (HNF1B) is transcription factor which plays a crucial role in the regulation of the development of several organs, but also seems to be implicated in the development of certain tumours, especially the subset of clear cell carcinomas of the ovary and kidney. Depending on the type of the tumour, HNF1B may act as either a tumour suppressor or an oncogene, although the exact mechanism by which HNF1B participates in the process of cancerogenesis is unknown. Using immunohistochemical approach and methylation and mutation analysis, we have investigated the expression, epigenetic, and genetic changes of HNF1B on 40 cases of colorectal adenomas and 105 cases of colorectal carcinomas. The expression of HNF1B was correlated with the benign or malignant behaviour of the lesion, given that carcinomas showed significantly lower levels of expression compared to adenomas. In carcinomas, lower levels of HNF1B expression were associated with recurrence and shortened disease-free survival. The mutation analysis revealed three somatic mutations (two frameshift and one nonsense) in the carcinoma sample set. Promoter methylation was detected in three carcinomas. These results suggest that in colorectal cancer, HNF1B may play a part in the pathogenesis and act in a tumour suppressive fashion.

A rare splice site mutation in the gene encoding glucokinase/hexokinase 4 in a patient with MODY type 2

The article presents a variant of maturity onset diabetes of the young type 2, caused by a rare mutation in the GCK gene. Maturity onset diabetes of the young (MODY) is a hereditary form of diabetes with an autosomal dominant type of inheritance, an onset at a young age, and a primary defect in pancreatic β-cell function. This type of diabetes is different from classical types of diabetes mellitus (DM1 and DM2) in its clinical course, treatment strategies, and prognosis. Clinical manifestations of MODY are heterogeneous and may vary even among members of the same family, i. e., carriers of identical mutations. This phenotypic variation is due to the interaction of mutations with different genetic backgrounds and the influence of environmental factors (e. g., lifestyle). Using next-generation sequencing technology, the c.580–1G>A substitution (IVS5 –1G>A, rs1554335421) located in an acceptor splice site of intron 5 of the GCK gene was found in a proband. The identified variant cosegregated with a pathological phenotype in the examined family members. The GCK gene encodes glucokinase (hexokinase 4), which catalyzes the first step in a large number of glucose metabolic pathways such as glycolysis. Mutations in this gene are the cause of MODY2. The illness is characterized by an insignificant increase in the fasting glucose level, is a well-controlled disease without medication, and has a low prevalence of micro- and macrovascular complications of diabetes. The presented case of MODY2 reveals the clinical significance of a mutation in the splice site of the GCK gene. When nonclassical diabetes mellitus is being diagnosed in young people and pregnant women, genetic testing is needed to verify the diagnosis and to select the optimal treatment method. Key words: human; maturity onset diabetes of the young; MODY2; glucokinase gene; next-generation sequencing; genetic analysis; bioinformatics.

Genetics and Pathophysiology of Maturity-onset Diabetes of the Young (MODY): A Review of Current Trends

Single gene mutations have been implicated in the pathogenesis of a form of diabetes mellitus (DM) known as the maturity-onset diabetes of the young (MODY). However, there are diverse opinions on the suspect genes and pathophysiology, necessitating the need to review and communicate the genes to raise public awareness. We used the Google search engine to retrieve relevant information from reputable sources such as PubMed and Google Scholar. We identified 14 classified MODY genes as well as three new and unclassified genes linked with MODY. These genes are fundamentally embedded in the beta cells, the most common of which are HNF1A, HNF4A, HNF1B, and GCK genes. Mutations in these genes cause β-cell dysfunction, resulting in decreased insulin production and hyperglycemia. MODY genes have distinct mechanisms of action and phenotypic presentations compared with type 1 and type 2 DM and other forms of DM. Healthcare professionals are therefore advised to formulate drugs and treatment based on the causal genes rather than the current generalized treatment for all types of DM. This will increase the effectiveness of diabetes drugs and treatment and reduce the burden of the disease.

Identification of novel HNF1B mRNA splicing variants and their qualitative and semi-quantitative profile in selected healthy and tumour tissues

Hepatocyte nuclear factor-1-beta (HNF1B) is a transcription factor crucial for the development of several tissues, and a promising biomarker of certain solid tumours. Thus far, two HNF1B alternative splicing variants (ASVs) have been described, however, the complete spectrum, prevalence and role of HNF1B ASVs in tumorigenesis are unclear. Considering the equivocal data about HNF1B ASVs and expression presented in literature, our aim was to characterize the spectrum of HNF1B mRNA splicing variants across different tissues. Here, we characterize HNF1B ASVs with high sensitivity in carcinomas of the uterine corpus, large intestine, kidney, pancreas, and prostate, with selected paired healthy tissues, using the previously described multiplex PCR and NGS approach. We identified 45 ASVs, of which 43 were novel. The spectrum and relative quantity of expressed ASVs mRNA differed among the analysed tissue types. Two known (3p, Δ7_8) and two novel (Δ7, Δ8) ASVs with unknown biological functions were detected in all the analysed tissues in a higher proportion. Our study reveals the wide spectrum of HNF1B ASVs in selected tissues. Characterization of the HNF1B ASVs is an important prerequisite for further expression studies to delineate the HNF1B splicing pattern, potential ASVs functional impact, and eventual refinement of HNF1B's biomarker role.

Review of current status of molecular diagnosis and characterization of monogenic diabetes mellitus: a focus on next-generation sequencing

Introduction: Monogenic diabetes is a subset of diabetes characterized by the presence of single-gene mutations and includes neonatal diabetes mellitus and maturity-onset diabetes of the young. Due to the genetic etiology of monogenic diabetes, molecular genetic testing can be used for diagnosis and classification.Areas covered: In addition to first-generation molecular analyses, many large clinical laboratories are transitioning to multiplexed next-generation sequencing panels to simultaneously assess patients for several of the most common genetic mutations seen in monogenic diabetes. With expanded development and adoption of next-generation sequencing panels, particularly in reference to laboratory settings, diagnostic testing for monogenic diabetes has the potential to be more accessible to the patient population.Expert opinion: Although molecular diagnostic testing is becoming increasingly prevalent, it is crucial to identify patients most likely to benefit from molecular testing versus those whose disease can be diagnosed and characterized with more traditional, less costly laboratory analyses. The continuous evolution of clinical molecular testing will be echoed in the clinical laboratory analysis of monogenic diabetes and continue to improve the diagnostic capabilities for monogenic diabetes mellitus.

A Recent Achievement In the Discovery and Development of Novel Targets for the Treatment of Type-2 Diabetes Mellitus

Type 2 diabetes (T2DM) is a chronic metabolic disorder. Impaired insulin secretion, enhanced hepatic glucose production, and suppressed peripheral glucose use are the main defects responsible for developing the disease. Besides, the pathophysiology of T2DM also includes enhanced glucagon secretion, decreased incretin secretion, increased renal glucose reabsorption, and adipocyte, and brain insulin resistance. The increasing prevalence of T2DM in the world beseeches an urgent need for better treatment options. The antidiabetic drugs focus on control of blood glucose concentration, but the future treatment goal is to delay disease progression and treatment failure, which causes poorer glycemic regulation. Recent treatment approaches target on several novel pathophysiological defects present in T2DM. Some of the promising novel targets being under clinical development include those that increase insulin sensitization (antagonists of glucocorticoids receptor), decreasing hepatic glucose production (glucagon receptor antagonist, inhibitors of glycogen phosphorylase and fructose-1,6-biphosphatase). This review summarizes studies that are available on novel targets being studied to treat T2DM with an emphasis on the small molecule drug design. The experience gathered from earlier studies and knowledge of T2DM pathways can guide the anti-diabetic drug development toward the discovery of drugs essential to treat T2DM.

Monogenic Diabetes: Genetics and Relevance on Diabetes Mellitus Personalized Medicine

BACKGROUND

Diabetes mellitus (DM) is a complex disease with significant impression in today's world. Aside from the most common types recognized over the years, such as type 1 diabetes (T1DM) and type 2 diabetes (T2DM), recent studies have emphasized the crucial role of genetics in DM, allowing the distinction of monogenic diabetes.

METHODS

Authors did a literature search with the purpose of highlighting and clarifying the subtypes of monogenic diabetes, as well as the accredited genetic entities responsible for such phenotypes.

RESULTS

The following subtypes were included in this literature review: maturity-onset diabetes of the young (MODY), neonatal diabetes mellitus (NDM) and maternally inherited diabetes and deafness (MIDD). So far, 14 subtypes of MODY have been identified, while three subtypes have been identified in NDM - transient, permanent, and syndromic.

DISCUSSION

Despite being estimated to affect approximately 2% of all the T2DM patients in Europe, the exact prevalence of MODY is still unknown, accentuating the need for research focused on biomarkers. Consequently, due to its impact in the course of treatment, follow-up of associated complications, and genetic implications for siblings and offspring of affected individuals, it is imperative to diagnose the monogenic forms of DM accurately.

CONCLUSION

Currently, advances in the genetics field allowed the recognition of new DM subtypes, which until now, were considered slight variations of the typical forms. Thus, it is imperative to act in the close interaction between genetics and clinical manifestations, to facilitate diagnosis and individualize treatment.

Nutritional Interventions and Considerations for the Development of Low Calorie or Sugar Free Foods

Diabetes is a globally prevalent chronic metabolic disease characterized by blood glucose levels higher than the normal levels. Sugar, a common constituent of diet, is also a major factor often responsible for elevating the glucose level in diabetic patients. However, diabetic patients are more prone to eat sweets amongst the human population. Therefore, we find a popular consumption of zero or low-calorie sweeteners, both natural and artificial. But, the uses of these sweeteners have proved to be controversial. Thus, the purpose of this review was to critically analyze and highlight the considerations needed for the development of sugar-free or low-calorie products for diabetic patients. For this purpose, various measures are taken such as avoiding sugary foods, using natural nectar, artificial sweeteners, etc. It cannot be ignored that many health hazards are associated with the overconsumption of artificial sweeteners only. These sweeteners are high-risk compounds and a properly balanced consideration needs to be given while making a diet plan for diabetic patients.

Dissimilar associations of same metabolic parameters with main chronic noncommunicable diseases (cancer vs some other NCDs)

Hormone-dependent tissues' cancers (mainly breast and endometrial and several others) are among the most frequent malignancies in adults and are often discussed in context of their correlation with other chronic noncommunicable diseases (NCDs), for example, cardiovascular and cerebrovascular conditions, and their risk factors, which may also be hormone metabolic. An idea that is often expressed delineates common factors leading to NCDs of malignant and nonmalignant nature. However, this idea is not always confirmed by study results. The reasons for this discrepancy are not clear and require further analysis. This editorial tries to show the importance of this problem with a few examples (in particular, by attracting information on the role of birthweight, adult height and family history of diabetes) which may help us understand some mechanisms behind interconnections of major NCDs, including cancer.

MODY2 diagnostic issues in adults

Approximately 90% of all cases of diabetes mellitus in adults involve type 2 diabetes, while the prevalence of maturity-onset diabetes of the young (MODY) remains undetermined leading to inappropriate treatment regimens. One of the most common monogenic forms of diabetes is a disease caused by a mutation in the glucokinase gene, MODY2. Knowledge of the clinical features of the disease allows the selection of patients with a high risk of mutation in the glucokinase gene and verification of diagnosis for molecular genetic research. This paper reflects the clinical features of MODY2 and the difficulties of diagnosis in adults. Furthermore, it presents a clinical case of a patient with MODY2 demonstrating all the features of this type of diabetes. A family member with a mutation in the gene allows to predict the nature of carbohydrate metabolism disorders in first degree relatives. A targeted study of only one part of the glucokinase gene in molecular genetic research is sufficient to confirm the diagnosis in relatives.

Using Clinical Indices to Distinguish MODY2 (GCK Mutation) and MODY3 (HNF1A Mutation) from Type 1 Diabetes in a Young Chinese Population

INTRODUCTION

Accurate diagnosis of maturity-onset diabetes of the young (MODY) is required in order to select appropriate treatment options and to assess prognosis. The aim of this study was to explore potential clinical indicators that could be used to differentiate MODY2, MODY3, and type 1 diabetes (T1D) in young subjects.

METHODS

Twelve patients with MODY3 and 29 patients with MODY2 were characterized and compared to 26 patients with T1D. These three groups were matched for age and gender. Clinical profiles of the 67 patients were collected. Receiver operating characteristic (ROC) curves were used to identify the optimal cutoff values of clinical indicators.

RESULTS

Compared to patients with T1D, subjects with MODY3 had higher fasting C-peptide levels (1.34 ± 1.51 vs. 0.29 ± 0.22 ng/mL; P  < 0.001) and lower high-sensitivity C-reactive protein (hsCRP) levels (0.18 ± 0.15 vs. 1.22 ± 1.49 mg/L, P  = 0.004); patients with MODY2 had lower hsCRP (0.37 ± 0.39 vs. 1.22 ± 1.49 mg/L; P  = 0.003), total cholesterol (4.12 ± 0.68 vs. 4.61 ± 0.81 mmol/L, P  = 0.034), and low-density lipoprotein cholesterol (LDL-C) (2.24 ± 0.68 vs. 2.67 ± 0.79 ng/L, P  = 0.002) levels and higher fasting C-peptide levels (0.96 ± 0.42 vs. 0.29 ± 0.22 ng/mL, P  = 0.002). The ROC-derived hsCRP values for discriminating MODY2 from T1D, MODY3 from T1D, and MODY3 from MODY2 were 0.675, 0.833, and 0.763, respectively. The ROC-derived fasting C-peptide levels for discriminating MODY2 from T1D and MODY3 from T1D were 0.951 and 0.975, respectively. The ROC-derived total cholesterol and LDL-C values for discriminating MODY2 from T1D were 0.670 and 0.662, respectively; the ROC-derived triglyceride value for discriminating MODY3 from MODY2 was 0.756. Additionally, a combination of indicators permitted better discrimination of MODY subtypes than any single parameter.

CONCLUSION

Our findings suggest that fasting C-peptide, hsCRP, and lipid levels permit good discrimination among MODY2, MODY3, and T1D. These clinical indicators could be used as markers of MODY2 and MODY3 in young patients with diabetes.

Copy Number Variation in GCK in Patients With Maturity-Onset Diabetes of the Young

PURPOSE

Next generation sequencing (NGS) methods to diagnose maturity-onset diabetes of the young (MODY), a monogenic autosomal dominant cause of diabetes, do not typically detect large-scale copy number variations (CNVs). New techniques may allow assessment for CNVs using output data from targeted NGS, without requiring additional sequencing. Using this technique, two kindreds of patients presenting with features of MODY were found to bear the same heterozygous large-scale deletion in GCK.

METHODS

Patients suspected of having MODY but with negative targeted NGS pathogenic variant calling were reanalyzed using the CNV caller tool (VarSeq v1.4.3). Two patients were identified as having a possible heterozygous whole exon deletion affecting exon 1 of GCK. For confirmation and determination of the exact breakpoints, whole exome sequencing followed by Sanger sequencing were used. Familial samples from both affected and nonaffected first-degree relatives were then analyzed for each proband.

RESULTS

A heterozygous whole-exon deletion spanning 4763 bp affecting the entire exon 1 of GCK was detected in two apparently unrelated patients with clinical features of MODY. This deletion showed segregation concordance across generations in affected and nonaffected family members.

CONCLUSIONS

Our findings confirm the utility of applying the CNV caller tool to screen for CNVs in GCK from NGS data. In so doing, we identified a deletion of exon 1 of GCK as likely causal for MODY. Our data indicate that incorporating CNV analysis routinely when assessing for MODY via targeted NGS may increase diagnostic yield and reduce false negative genetic testing rates.

Maturity Onset Diabetes of the Young is Not Necessarily Associated with Autosomal Inheritance: Case Description of a De Novo HFN1A Mutation

Maturity onset diabetes of the young (MODY) accounts for up to 4% of all cases of diabetes in pediatric patients. MODY is usually characterized by autosomal dominant inheritance, impaired insulin secretion, and an average age at diagnosis of 18-26 years. Mutations in the hepatocyte nuclear factor 1-alpha (HNF1A), glucokinase, hepatocyte nuclear factor 4-alpha, and hepatocyte nuclear factor 1-beta genes are the mutations most frequently observed in cases of MODY. We herein report a case of HNF1A-MODY characterized by an early onset of diabetes. Genetic investigations revealed a de novo heterozygous substitution, N237D (HNF1A c.709A>G), in exon 3 of the HNF1A gene. Our case supports the hypothesis that de novo mutations are more frequent than expected. This recent evidence may suggest that conventional clinical diagnostic criteria for MODY should be revised and personalized according to the individual patient.

Identification of a novel mutation site in maturity‑onset diabetes of the young in a Chinese family by whole‑exome sequencing

The aim of the present study was to determine the mutant genes and mutation sites in a family with maturity-onset diabetes of the young (MODY), in order to provide evidence for the diagnosis and treatment of clinical MODY. Based on the clinical characteristics of MODY, one family was selected from the Department of Endocrinology of Shanxi Provincial People's Hospital (Shanxi, China). The family comprised seven individuals, four of which were healthy (without MODY), and the whole exome of the individual with MODY, her father and her mother were sequenced. A suspected case (patient's uncle) and a healthy individual (patient's aunt) were sequenced for verification. The Q30 ratio was >90% in the family of three and the sequencing quality was good. The alignment rate was >95%, while the repeat sequence was <10%, with a mean sequencing depth of >120×, which is sufficient to identify mutations. According to Mutation Taster and LRT, it was predicted that the p.leu73Pro mutation of the pancreatic and duodenal homeobox 1 (PDX1) gene was deleterious. The mutation was verified by next-generation sequencing as the pathogenic site in this family. In conclusion, a novel mutation site of MODY type 4 in the PDX1 gene was identified in a family with MODY, which may provide a basis for its clinical treatment. Whole-exome sequencing appears to be of assistance in accurately diagnosing MODY.

Genetic characterization of suspected MODY patients in Tunisia by targeted next-generation sequencing

AIMS

Maturity Onset Diabetes of the Young (MODY) is a monogenic form of diabetes with autosomal dominant inheritance pattern. The diagnosis of MODY and its subtypes is based on genetic testing. Our aim was investigating MODY by means of next-generation sequencing in the Tunisian population.

METHODS

We performed a targeted sequencing of 27 genes known to cause monogenic diabetes in 11 phenotypically suspected Tunisian patients. We retained genetic variants passing filters of frequency in public databases as well as their probable effects on protein structures and functions evaluated by bioinformatics prediction tools.

RESULTS

Five heterozygous variants were found in four patients. They include two mutations in HNF1A and GCK that are the causative genes of the two most prevalent MODY subtypes described in the literature. Other possible mutations, including novel frameshift and splice-site variants were identified in ABCC8 gene.

CONCLUSIONS

Our study is the first to investigate the clinical application of targeted next-generation sequencing for the diagnosis of MODY in Africa. The combination of this approach with a filtering/prioritization strategy made a step towards the identification of MODY mutations in the Tunisian population.

Precision medicine in diabetes prevention, classification and management

Diabetes has become a major burden of healthcare expenditure. Diabetes management following a uniform treatment algorithm is often associated with progressive treatment failure and development of diabetic complications. Recent advances in our understanding of the genomic architecture of diabetes and its complications have provided the framework for development of precision medicine to personalize diabetes prevention and management. In the present review, we summarized recent advances in the understanding of the genetic basis of diabetes and its complications. From a clinician's perspective, we attempted to provide a balanced perspective on the utility of genomic medicine in the field of diabetes. Using genetic information to guide management of monogenic forms of diabetes represents the best-known examples of genomic medicine for diabetes. Although major strides have been made in genetic research for diabetes, its complications and pharmacogenetics, ongoing efforts are required to translate these findings into practice by incorporating genetic information into a risk prediction model for prioritization of treatment strategies, as well as using multi-omic analyses to discover novel drug targets with companion diagnostics. Further research is also required to ensure the appropriate use of this information to empower individuals and healthcare professionals to make personalized decisions for achieving the optimal outcome.

Pathophysiology-based phenotyping in type 2 diabetes: A clinical classification tool

BACKGROUND

Type 2 diabetes may be a more heterogeneous disease than previously thought. Better understanding of pathophysiological subphenotypes could lead to more individualized diabetes treatment. We examined the characteristics of different phenotypes among 5813 Danish patients with new clinically diagnosed type 2 diabetes.

METHODS

We first identified all patients with rare subtypes of diabetes, latent autoimmune diabetes of adults (LADA), secondary diabetes, or glucocorticoid-associated diabetes. We then used the homeostatic assessment model to subphenotype all remaining patients into insulinopenic (high insulin sensitivity and low beta cell function), classical (low insulin sensitivity and low beta cell function), or hyperinsulinemic (low insulin sensitivity and high beta cell function) type 2 diabetes.

RESULTS

Among 5813 patients diagnosed with incident type 2 diabetes in the community clinical setting, 0.4% had rare subtypes of diabetes, 2.8% had LADA, 0.7% had secondary diabetes, 2.4% had glucocorticoid-associated diabetes, and 93.7% had WHO-defined type 2 diabetes. In the latter group, 9.7% had insulinopenic, 63.1% had classical, and 27.2% had hyperinsulinemic type 2 diabetes. Classical patients were obese (median waist 105 cm), and 20.5% had cardiovascular disease (CVD) at diagnosis, while insulinopenic patients were fairly lean (waist 92 cm) and 17.5% had CVD (P = 0.14 vs classical diabetes). Hyperinsulinemic patients were severely obese (waist 112 cm), and 25.5% had CVD (P < 0.0001 vs classical diabetes).

CONCLUSIONS

Patients clinically diagnosed with type 2 diabetes are a heterogeneous group. In the future, targeted treatment based on pathophysiological characteristics rather than the current "one size fits all" approach may improve patient prognosis.

An Atypical HNF4A Mutation Which Does Not Conform to the Classic Presentation of HNF4A-MODY

Objective

To present the case of an atypical Hepatocyte Nuclear Factor 4 Alpha (HNF4A) mutation that is not consistent with the classically published presentation of HNF4A-Mature Onset Diabetes of the Young (MODY).

Methods

Clinical presentation and literature review.

Results

A 43-year-old nonobese man was referred to the endocrinology clinic for evaluation of elevated fasting blood glucose (FBG) measurements. Laboratory review revealed prediabetes and hypertriglyceridemia for the previous decade. Testing of autoantibodies for type 1 diabetes was negative. Genetic testing showed an autosomal dominant, heterozygous missense mutation (c.991C>T; p.Arg331Cys) in the HNF4A gene, which is correlated with HNF4A-MODY. Phenotypically, patients with an HNF4A-MODY tend to have early-onset diabetes, microvascular complications, low triglyceride levels, increased birth weight, fetal macrosomia, and less commonly neonatal hyperinsulinemic hypoglycemia. The patient did not demonstrate any of these features but instead presented with late-onset diabetes, an elevated triglyceride level, and a normal birth weight.

Conclusion

Our patient likely represents an atypical variant of HNF4A-MODY with a milder clinical presentation. Patients with atypical, less-severe presentations of HNF4A-MODY may be largely undiagnosed or misdiagnosed, but identification is important due to implications for treatment, pregnancy, and screening of family members.

Determination of the mutational landscape in Taiwanese patients with papillary thyroid cancer by whole-exome sequencing

Among women in Taiwan, thyroid cancer is the fifth most common malignant neoplasia. However, genomic profiling of papillary thyroid cancer (PTC) cases from Taiwan has not been attempted previously. We used whole-exome sequencing to identify mutations in a cohort of 19 PTC patients. Sequencing was performed using the Illumina system; Sanger sequencing was used to validate all identified mutations. We identified new somatic mutations in APC, DICER1, LRRC8D and NDRG1. We also found somatic mutations in ARID5A, CREB3L2, MDM4, PPP2R5A and TFPT; mutations in these genes had been found previously in other tumors, but had not been described previously in PTC. We also investigated the pathway deregulation in BRAF-mutated PTC compared with wild-type BRAF PTC. In checking our gene mutations against The Cancer Genome Atlas (TCGA) database, we identified aberrations in one pathway that are specific to BRAF-mutated PTC: maturity-onset diabetes of the young. In addition, the caffeine metabolism pathway showed aberrations that are specific to wild-type BRAF PTC. For this study, we performed a comprehensive exome-wide analysis of the mutational spectra of Taiwanese patients with PTC. We identified novel genes that are potentially associated with PTC tumorigenesis, as well as aberrations in pathways that led to the distinct pathogeneses of BRAF-mutated PTC and wild-type BRAF PTC, which may provide a new target for PTC therapy.

Genomic integration of ERRγ-HNF1β regulates renal bioenergetics and prevents chronic kidney disease

Mitochondrial dysfunction is increasingly recognized as a critical determinant of both hereditary and acquired kidney diseases. However, it remains poorly understood how mitochondrial metabolism is regulated to support normal kidney function and how its dysregulation contributes to kidney disease. Here, we show that the nuclear receptor estrogen-related receptor gamma (ERRγ) and hepatocyte nuclear factor 1 beta (HNF1β) link renal mitochondrial and reabsorptive functions through coordinated epigenomic programs. ERRγ directly regulates mitochondrial metabolism but cooperatively controls renal reabsorption via convergent binding with HNF1β. Deletion of ERRγ in renal epithelial cells (RECs), in which it is highly and specifically expressed, results in severe renal energetic and reabsorptive dysfunction and progressive renal failure that recapitulates phenotypes of animals and patients with HNF1β loss-of-function gene mutations. Moreover, ERRγ expression positively correlates with renal function and is decreased in patients with chronic kidney disease (CKD). REC-ERRγ KO mice share highly overlapping renal transcriptional signatures with human patients with CKD. Together these findings reveal a role for ERRγ in directing independent and HNF1β-integrated programs for energy production and use essential for normal renal function and the prevention of kidney disease.

Role of conventional immunomarkers, HNF4-α and SATB2, in the differential diagnosis of pulmonary and colorectal adenocarcinomas

AIMS

Pulmonary (ADC) and colorectal (CRC) adenocarcinomas are frequent entities in pathological routine diagnostics. Whereas the differential diagnosis is usually straightforward based on histomorphology, it can be challenging in small biopsies. In general, CDX-2, CK20, Napsin-A and TTF-1 are recommended immunohistological markers in this scenario. Hepatocyte nuclear factor 4 alpha (HNF4-α) and special AT-rich sequence-binding protein 2 (SATB2) were described recently as promising additional markers, but comprehensive large-scale data are lacking so far. Therefore, we analysed the expression of these six markers in 1021 non-small-cell lung cancers (NSCLC), including 472 ADC as well as in 80 pulmonary metastases of CRC.

METHODS AND RESULTS

Tissue microarrays of NSCLC and pulmonary metastases of CRC were stained for CDX-2, CK20, HNF4-α, Napsin-A, SATB2 and TTF-1 and staining results were correlated with clinicopathological variables. ADC exhibited expression of CDX-2, CK20, HNF4-α, Napsin-A, SATB2 and TTF-1 in nine (2%), 21 (4%), 17 (4%), 345 (73%), 35 (7%) and 408 (86%) samples, while 80 CRC were positive in 79 (99%), 74 (93%), 77 (96%), no (0%), 78 (98%) and five (6%) cases, respectively.

CONCLUSIONS

In addition to conventional immunomarkers, HNF4-α and particularly SATB2 may be helpful in the differential diagnosis of pulmonary ADC and metastases of CRC.

Comprehensive genomic analysis identifies pathogenic variants in maturity-onset diabetes of the young (MODY) patients in South India

BACKGROUND

Maturity-onset diabetes of the young (MODY) is an early-onset, autosomal dominant form of non-insulin dependent diabetes. Genetic diagnosis of MODY can transform patient management. Earlier data on the genetic predisposition to MODY have come primarily from familial studies in populations of European origin.

METHODS

In this study, we carried out a comprehensive genomic analysis of 289 individuals from India that included 152 clinically diagnosed MODY cases to identify variants in known MODY genes. Further, we have analyzed exome data to identify putative MODY relevant variants in genes previously not implicated in MODY. Functional validation of MODY relevant variants was also performed.

RESULTS

We found MODY 3 (HNF1A; 7.2%) to be most frequently mutated followed by MODY 12 (ABCC8; 3.3%). They together account for ~ 11% of the cases. In addition to known MODY genes, we report the identification of variants in RFX6, WFS1, AKT2, NKX6-1 that may contribute to development of MODY. Functional assessment of the NKX6-1 variants showed that they are functionally impaired.

CONCLUSIONS

Our findings showed HNF1A and ABCC8 to be the most frequently mutated MODY genes in south India. Further we provide evidence for additional MODY relevant genes, such as NKX6-1, and these require further validation.

Use of oral antidiabetic drugs in the treatment of maturity-onset diabetes of the young: A mini review

MODY (maturity-onset diabetes of the young) is a genetically linked group of clinically heterogeneous subtypes of diabetes. Roughly 5% of people with diabetes mellitus diagnosed prior to age 45 have MODY diabetes. Most of them have been erroneously diagnosed as patients with either type 1 or type 2 diabetes and, as a result, have been improperly treated. Genetic identification of MODY diabetes and its subtypes allows proper treatment and enables clinicians to switch many patients to oral antidiabetic agents, mainly sulphonylureas. However, some new classes of oral antidiabetic drugs have also been tested and found to be effective in MODY patients. We have searched for research articles and case reports written in full-text English or with an English abstract, using the following keywords: MODY and oral antidiabetic* in the databases Cochrane Library, PubMed, and Science Direct. Therapeutic options using currently standardized oral antidiabetic drugs (mainly sulphonylureas), as well as more experimental treatment with other classes of oral antidiabetic drugs in different types of MODY, are discussed, with special focus on the therapy of the most common MODY subtypes, including specific conditions such as pregnancy. This review article summarizes the currently available information about oral antidiabetic treatment of patients with MODY diabetes.

Renal development in the fetus and premature infant

Congenital abnormalities of the kidney and urinary tract (CAKUT) are one of the leading congenital defects to be identified on prenatal ultrasound. CAKUT represent a broad spectrum of abnormalities, from transient hydronephrosis to severe bilateral renal agenesis. CAKUT are a major contributor to chronic and end stage kidney disease (CKD/ESKD) in children. Prenatal imaging is useful to identify CAKUT, but will not detect all defects. Both genetic abnormalities and the fetal environment contribute to CAKUT. Monogenic gene mutations identified in human CAKUT have advanced our understanding of molecular mechanisms of renal development. Low nephron number and solitary kidneys are associated with increased risk of adult onset CKD and ESKD. Premature and low birth weight infants represent a high risk population for low nephron number. Additional research is needed to identify biomarkers and appropriate follow-up of premature and low birth weight infants into adulthood.

Sex-gender-related therapeutic approaches for cardiovascular complications associated with diabetes

Diabetes is a chronic disease associated with micro- and macrovascular complications and is a well-established risk factor for cardiovascular disease. Cardiovascular complications associated with diabetes are among the most important causes of death in diabetic patients. Interestingly, several sex-gender differences have been reported to significantly impact in the pathophysiology of diabetes. In particular, sex-gender differences have been reported to affect diabetes epidemiology, risk factors, as well as cardiovascular complications associated with diabetes. This suggests that different therapeutic approaches are needed for managing diabetes-associated cardiovascular complications in men and women. In this review, we will discuss about the sex-gender differences that are known to impact on diabetes, mainly focusing on the cardiovascular complications associated with the disease. We will then discuss the therapeutic approaches for managing diabetes-associated cardiovascular complications and how differences in sex-gender can influence the existing therapeutic approaches.

Derangement of calcium metabolism in diabetes mellitus: negative outcome from the synergy between impaired bone turnover and intestinal calcium absorption

Both types 1 and 2 diabetes mellitus (T1DM and T2DM) are associated with profound deterioration of calcium and bone metabolism, partly from impaired intestinal calcium absorption, leading to a reduction in calcium uptake into the body. T1DM is associated with low bone mineral density (BMD) and osteoporosis, whereas the skeletal changes in T2DM are variable, ranging from normal to increased and to decreased BMD. However, both types of DM eventually compromise bone quality through production of advanced glycation end products and misalignment of collagen fibrils (so-called matrix failure), thereby culminating in a reduction of bone strength. The underlying cellular mechanisms (cellular failure) are related to suppression of osteoblast-induced bone formation and bone calcium accretion, as well as to enhancement of osteoclast-induced bone resorption. Several other T2DM-related pathophysiological changes, e.g., osteoblast insulin resistance, impaired productions of osteogenic growth factors (particularly insulin-like growth factor 1 and bone morphogenetic proteins), overproduction of pro-inflammatory cytokines, hyperglycemia, and dyslipidemia, also aggravate diabetic osteopathy. In the kidney, DM and the resultant hyperglycemia lead to calciuresis and hypercalciuria in both humans and rodents. Furthermore, DM causes deranged functions of endocrine factors related to mineral metabolism, e.g., parathyroid hormone, 1,25-dihydroxyvitamin D3, and fibroblast growth factor-23. Despite the wealth of information regarding impaired bone remodeling in DM, the long-lasting effects of DM on calcium metabolism in young growing individuals, pregnant women, and neonates born to women with gestational DM have received scant attention, and their underlying mechanisms are almost unknown and worth exploring.

Genetic diagnosis and treatment of a Chinese ketosis-prone MODY 3 family with depression

BACKGROUND

To analyze the gene mutation and mental disorder of a Chinese ketosis-prone diabetes (KPD) family, and to make a precise diagnosis and give a treatment for them.

METHODS

We studied a Chinese family with a clinical diagnosis of maturity-onset diabetes of the young (MODY). The clinical data and the blood samples were collected. The promotor and coding regions inclusive intron exon boundaries of the HNF1A, HNF4A were detected by polymerase chain reaction (PCR) and direct sequencing. The missense mutation was also analyzed by bioinformatics. Genetic counseling was performed twice a month to relieve the mental disorder of the persons.

RESULTS

The missense mutation c.779 C>T (p.T260M) in exon4 of HNF1A gene was detected, and the symptom heterogenicity among persons in this family were found. All the members were retreated with Gliclazide and stopped to use other medicine, the blood glucose of them were well controlled. We also performed an active genetic counseling to them and the mental disorder of the proband's sister was relieved.

CONCLUSIONS

A missense mutation of HNF1A gene was first found in Chinese ketosis-prone MODY family with manifestations heterogenicity among the persons. Sulphonylureas medicine and genetic counseling are efficiency ways to treat MODY 3 and its' mental disorder respectively.