Clinical features, epidemiology, autoantibody status, HLA haplotypes and genetic mechanisms of type 1 diabetes mellitus among children in Qatar

The epidemiology of type 1 diabetes mellitus in older adults

Although type 1 diabetes mellitus (T1DM) is traditionally viewed as a youth-onset disorder, the number of older adults being diagnosed with this disease is growing. Improvements in the average life expectancy of people with T1DM have also contributed to the growing number of older people living with this disease. We summarize the evidence regarding the epidemiology (incidence, prevalence and excess mortality) of T1DM in older adults (ages ≥60 years) as well as the genetics, immunology and diagnostic challenges. Several studies report an incidence peak of T1DM in older adults of a similar size to or exceeding that in children, and population prevalence generally increases with increasing age. Glutamic acid decarboxylase antibody positivity is frequently observed in adult-onset T1DM. Guidelines for differentiating T1DM from type 2 diabetes mellitus in older adults recommend measuring levels of C-peptide and autoantibodies, including glutamic acid decarboxylase antibodies. However, there is no gold standard for differentiating T1DM from type 2 diabetes mellitus in people aged 60 years and over. As such, the global variation observed in T1DM epidemiology might be in part explained by misclassification, which increases with increasing age of diabetes mellitus onset. With a growing global population of older adults with T1DM, improved genetic and immunological evidence is needed to differentiate diabetes mellitus type at older ages so that a clear epidemiological picture can emerge.

Epidemiological status, development trends, and risk factors of disability-adjusted life years due to diabetic kidney disease: A systematic analysis of Global Burden of Disease Study 2021

BACKGROUND

Approximately 40% of individuals with diabetes worldwide are at risk of developing diabetic kidney disease (DKD), which is not only the leading cause of kidney failure, but also significantly increases the risk of cardiovascular disease, causing significant societal health and financial burdens. This study aimed to describe the burden of DKD and explore its cross-country epidemiological status, predict development trends, and assess its risk factors and sociodemographic transitions.

METHODS

Based on the Global Burden of Diseases (GBD) Study 2021, data on DKD due to type 1 diabetes (DKD-T1DM) and type 2 diabetes (DKD-T2DM) were analyzed by sex, age, year, and location. Numbers and age-standardized rates were used to compare the disease burden between DKD-T1DM and DKD-T2DM among locations. Decomposition analysis was used to assess the potential drivers. Locally weighted scatter plot smoothing and Frontier analysis were used to estimate sociodemographic transitions of DKD disability-adjusted life years (DALYs).

RESULTS

The DALYs due to DKD increased markedly from 1990 to 2021, with a 74.0% (from 2,228,000 to 3,876,000) and 173.6% (from 4,123,000 to 11,279,000) increase for DKD-T1DM and DKD-T2DM, respectively. In 2030, the estimated DALYs for DKD-T1DM surpassed 4.4 million, with that of DKD-T2DM exceeding 14.6 million. Notably, middle-sociodemographic index (SDI) quintile was responsible for the most significant DALYs. Decomposition analysis revealed that population growth and aging were major drivers for the increased DKD DALYs in most GBD regions. Interestingly, the most pronounced effect of positive DALYs change from 1990 to 2021 was presented in high-SDI quintile, while in low-SDI quintile, DALYs for DKD-T1DM and DKD-T2DM presented a decreasing trend over the past years. Frontiers analysis revealed that there was a negative association between SDI quintiles and age-standardized DALY rates (ASDRs) in DKD-T1DM and DKD-T2DM. Countries with middle-SDI shouldered disproportionately high DKD burden. Kidney dysfunction (nearly 100% for DKD-T1DM and DKD-T2DM), high fasting plasma glucose (70.8% for DKD-T1DM and 87.4% for DKD-T2DM), and non-optimal temperatures (low and high, 5.0% for DKD-T1DM and 5.1% for DKD-T2DM) were common risk factors for age-standardized DALYs in T1DM-DKD and T2DM-DKD. There were other specific risk factors for DKD-T2DM such as high body mass index (38.2%), high systolic blood pressure (10.2%), dietary risks (17.8%), low physical activity (6.2%), lead exposure (1.2%), and other environmental risks.

CONCLUSIONS

DKD markedly increased and varied significantly across regions, contributing to a substantial disease burden, especially in middle-SDI countries. The rise in DKD is primarily driven by population growth, aging, and key risk factors such as high fasting plasma glucose and kidney dysfunction, with projections suggesting continued escalation of the burden by 2030.

Association of the Immunity Genes with Type 1 Diabetes Mellitus

Type 1 diabetes mellitus (T1D) is a complicated illness marked by the death of insulin- producing pancreatic beta cells, which ultimately leads to insulin insufficiency and hyperglycemia. T lymphocytes are considered to destroy pancreatic beta cells in the etiology of T1D as a result of hereditary and environmental factors. Although the latter factors are very important causes of T1D development, this disease is very genetically predisposed, so there is a significant genetic component to T1D susceptibility. Among the T1D-associated gene mutations, those that affect genes that encode the traditional Human Leukocyte Antigens (HLA) entail the highest risk of T1D development. Accordingly, the results of decades of genetic linkage and association studies clearly demonstrate that mutations in the HLA genes are the most associated mutations with T1D. They can, therefore, be used as biomarkers for prediction strategies and may even prove to be of value for personalized treatments. Other immunity-associated genetic loci are also associated with higher T1D risk. Indeed, T1D is considered an autoimmune disease. Its prevalence is rising globally, especially among children and young people. Given the global rise of, and thus interest in, autoimmune diseases, here we present a short overview of the link between immunity, especially HLA, genes and T1D.

Potential contribution of gut microbiota in the development of autoantibodies in T1D children carrying HLA-DRB1/DQB1 risk alleles: an experimental and in silico analysis

This study aimed to investigate the prevalence of insulin autoantibody (IAA), glutamic acid decarboxylase antibody (GADA), and insulinoma-associated antigen-2 antibody (IA-2A) in type 1 diabetes (T1D) children based on the presence of predisposing HLA-II alleles. Additionally, to assess the sequence homology between autoantigens of islet cells and selected proteins derived from gut bacteria in terms of their binding capacities to HLA risk alleles, HLA-DRB1/DQB1 alleles were determined by PCR-SSOP in 111 T1D children (probands) along with 222 parents and 133 siblings. Autoantibodies were measured by ELISA, and in silico analysis was run as follows: protein extraction, homology and epitope prediction, peptide alignment, and HLA-peptide docking. Higher significant frequencies of DRB1*03:01, DQB1*02:01, and DQB1*03:02 alleles and DRB1*03:01 ~ DQB1*02:01 haplotype and lower frequencies of DRB1*11:01, DRB1*14:01, and DQB1*03:01 alleles were found in probands compared to parents and siblings. DRB1*11:01 ~ DQB1*03:01, DRB1*14:01 ~ DQB1*05:03, and DRB1*15:01-DQB1*06:02 haplotypes were significantly less frequent in the probands compared to parents. Out of 111 probands, 21 were seronegative, 90 tested positive for one autoantibody, and 15 showed the concurrent presence of three autoantibodies. Logistic regression analysis revealed that DRB1*04 ~ DQB1*03:02 haplotype was associated with the induction of GADA and IA-2A, while DRB1*11:01 ~ DQB1*03:01 was associated with seronegativity. Epitopes derived from GAD and gut bacteria showed strong binding capacities to HLA risk alleles. Due to the sequence similarities between gut bacteria-derived proteins and islet cell autoantigens and their potential for binding to HLA risk alleles, dysbiosis of gut microbiota can be considered another risk factor for the development of T1D, especially in genetically susceptible individuals.

Factors associated with severe diabetic ketoacidosis in patients diagnosed with type 1 diabetes: a decade-long cross-sectional analysis

OBJECTIVE

The aim of this study was to identify factors associated with severe diabetic ketoacidosis (DKA) at the onset of type 1 diabetes mellitus (T1DM) in adult patients.

METHODS

We conducted a retrospective analysis over a 10-year period including adults newly diagnosed with T1DM. Eligible participants were diagnosed with DKA at the time of T1DM diagnosis. DKA severity was categorized as mild, moderate, or severe. Data were collected on age, body mass index, family history of diabetes and autoimmune disorders, lifestyle habits, delayed diagnosis, and preceding factors.

RESULTS

A total of 305 participants (69.8% men) with T1DM were included. Overall, 63 patients were admitted with severe DKA (Group 1) and 242 with non-severe DKA (Group 2). Factors associated with severe DKA at diagnosis of T1DM were a long period between symptom onset and first hospitalization, preceding infection, tachypnea, thrombocytopenia, anemia, hepatic cytolysis, polyuria, and tachycardia.

CONCLUSIONS

The present findings highlight the need for improving awareness about diabetes symptoms among physicians and the public to reduce the occurrence and severity of DKA at the onset of T1DM.

Fifty years of HLA-associated type 1 diabetes risk: history, current knowledge, and future directions

More than 50 years have elapsed since the association of human leukocyte antigens (HLA) with type 1 diabetes (T1D) was first reported. Since then, methods for identification of HLA have progressed from cell based to DNA based, and the number of recognized HLA variants has grown from a few to tens of thousands. Current genotyping methodology allows for exact identification of all HLA-encoding genes in an individual's genome, with statistical analysis methods evolving to digest the enormous amount of data that can be produced at an astonishing rate. The HLA region of the genome has been repeatedly shown to be the most important genetic risk factor for T1D, and the original reported associations have been replicated, refined, and expanded. Even with the remarkable progress through 50 years and over 5,000 reports, a comprehensive understanding of all effects of HLA on T1D remains elusive. This report represents a summary of the field as it evolved and as it stands now, enumerating many past and present challenges, and suggests possible paradigm shifts for moving forward with future studies in hopes of finally understanding all the ways in which HLA influences the pathophysiology of T1D.

Evaluation of HLA typing content of next-generation sequencing datasets from family trios and individuals of arab ethnicity

Introduction: HLA typing is a critical tool in both clinical and research applications at the individual and population levels. Benchmarking studies have indicated HLA-HD as the preferred tool for accurate and comprehensive HLA allele calling. The advent of next-generation sequencing (NGS) has revolutionized genetic analysis by providing high-throughput sequencing data. This study aims to evaluate, using the HLA-HD tool, the HLA typing content of whole exome, whole genome, and HLA-targeted panel sequence data from the consanguineous population of Arab ethnicity, which has been underrepresented in prior benchmarking studies. Methods: We utilized sequence data from family trios and individuals, sequenced on one or more of the whole exome, whole genome, and HLA-targeted panel sequencing technologies. The performance and resolution across various HLA genes were evaluated. We incorporated a comparative quality control analysis, assessing the results obtained from HLA-HD by comparing them with those from the HLA-Twin tool to authenticate the accuracy of the findings. Results: Our analysis found that alleles across 29 HLA loci can be successfully and consistently typed from NGS datasets. Clinical-grade whole exome sequencing datasets achieved the highest consistency rate at three-field resolution, followed by targeted HLA panel, research-grade whole exome, and whole genome datasets. Discussion: The study catalogues HLA typing consistency across NGS datasets for a large array of HLA genes and highlights assessments regarding the feasibility of utilizing available NGS datasets in HLA allele studies. These findings underscore the reliability of HLA-HD for HLA typing in underrepresented populations and demonstrate the utility of various NGS technologies in achieving accurate HLA allele calling.

Genetic and Epigenetic Aspects of Type 1 Diabetes Mellitus: Modern View on the Problem

Omics technologies accumulated an enormous amount of data that advanced knowledge about the molecular pathogenesis of type 1 diabetes mellitus and identified a number of fundamental problems focused on the transition to personalized diabetology in the future. Among them, the most significant are the following: (1) clinical and genetic heterogeneity of type 1 diabetes mellitus; (2) the prognostic significance of DNA markers beyond the HLA genes; (3) assessment of the contribution of a large number of DNA markers to the polygenic risk of disease progress; (4) the existence of ethnic population differences in the distribution of frequencies of risk alleles and genotypes; (5) the infancy of epigenetic research into type 1 diabetes mellitus. Disclosure of these issues is one of the priorities of fundamental diabetology and practical healthcare. The purpose of this review is the systemization of the results of modern molecular genetic, transcriptomic, and epigenetic investigations of type 1 diabetes mellitus in general, as well as its individual forms. The paper summarizes data on the role of risk HLA haplotypes and a number of other candidate genes and loci, identified through genome-wide association studies, in the development of this disease and in alterations in T cell signaling. In addition, this review assesses the contribution of differential DNA methylation and the role of microRNAs in the formation of the molecular pathogenesis of type 1 diabetes mellitus, as well as discusses the most currently central trends in the context of early diagnosis of type 1 diabetes mellitus.

Islet Autoantibodies to Pancreatic Insulin-Producing Beta Cells in Adolescent and Adults with Type 1 Diabetes Mellitus: A Cross-Sectional Study

(1) Background: Type 1 diabetes mellitus (T1D) is a chronic autoimmune disease caused by the destruction of pancreatic insulin-producing beta cells. T1D is one of the most common endocrine and metabolic disorders occurring in children. Autoantibodies against pancreatic insulin-producing beta cells are important immunological and serological markers of T1D. Zinc transporter 8 autoantibody (ZnT8) is a recently identified autoantibody in T1D; however, no data on ZnT8 autoantibody in the Saudi Arabian population have been reported. Thus, we aimed to investigate the prevalence of islet autoantibodies (IA-2 and ZnT8) in adolescents and adults with T1D according to age and disease duration. (2) Methods: In total, 270 patients were enrolled in this cross-sectional study. After meeting the study's inclusion and exclusion criteria, 108 patients with T1D (50 men and 58 women) were assessed for T1D autoantibody levels. Serum ZnT8 and IA-2 autoantibodies were measured using commercial enzyme-linked immunosorbent assay kits. (3) Results: IA-2 and ZnT8 autoantibodies were present in 67.6% and 54.6% of patients with T1D, respectively. Autoantibody positivity was found in 79.6% of the patients with T1D. Both the IA-2 and ZnT8 autoantibodies were frequently observed in adolescents. The prevalence of IA-2 and ZnT8 autoantibodies in patients with a disease duration < 1 year was 100% and 62.5%, respectively, which declined with an increase in disease duration (p < 0.020). Logistic regression analysis revealed a significant relationship between age and autoantibodies (p < 0.004). (4) Conclusions: The prevalence of IA-2 and ZnT8 autoantibodies in the Saudi Arabian T1D population appears to be higher in adolescents. The current study also showed that the prevalence of autoantibodies decreased with disease duration and age. IA-2 and ZnT8 autoantibodies are important immunological and serological markers for T1D diagnosis in the Saudi Arabian population.

Sib-pair subgroup familial type 1 diabetes mellitus in children in the state of Qatar

Background

Type 1 diabetes is the most common type of diabetes mellitus (DM) in children. It can be sporadic in onset or cluster in families, which comprises parent-offspring and sib-pair subgroups. The risk of developing DM in first-degree relatives of affected individuals is 8–15 fold higher. There is limited data about familial DM from the Gulf region. This study aims to describe the clinical, biochemical and genetic characteristics of sib-pair familial type 1 diabetes in Qatar.

Methods

Every child with DM following up at Sidra Medicine was recruited. Data was collected regarding clinical features, family history, type 1 diabetes autoantibodies and whole genome sequencing was performed. Genetic analysis for MODY genes and HLA association analysis was conducted.

Results

44 families with sib-pair familial diabetes were identified. Of these, 2 families had 4 affected siblings and 5 families had 3 affected siblings. The majority are of Qatari ethnicity and the most common autoantibody was GAD65. The most common age of onset in the proband was 5–9 years while it was 10–14 years in subsequent siblings. The occurrence of DKA & HbA1c levels were lower in the second affected sibling. No relevant MODY gene variants were found. HLA analysis found 15 variants in at least 50% of the subjects. Most common were HLA-F*01*01*01G, HLA- DPA1*01*03*01G, HLA- DRB3*02*02*01G, HLA- E*01*01*01G & DRB4*03*01N.

Conclusions

The prevalence of sib-pair diabetes is 3.64%. The second affected siblings were older. MODY is unlikely and Class I and II HLA genes was present in sib-pair diabetes.

Homozygous Insulin Promotor Gene Mutation Causing Permanent Neonatal Diabetes Mellitus and Childhood Onset Autoantibody Negative Diabetes in the Same Family

Purpose

To report a family with a homozygous INS promotor gene mutation causing permanent neonatal diabetes mellitus (PNDM) in one sibling and autoantibody negative childhood onset diabetes in another sibling.

Case Presentation

Patient 1 is a 12-year-old girl born at term with low birth weight to a consanguineous family, diagnosed with PNDM at 26 days of life. She presented with ketoacidosis and has a severe course of disease with high insulin requirement. Patient 2 is a 9-year-old girl born at term with normal weight, who presented with ketoacidosis at 2 years of age. Both subjects have negative type 1 autoantibodies. On genetic testing, a mutation in the promoter region of INS gene c.-331 C>G was found in homozygous state in both subjects and in a heterozygous state in parents.

Conclusion

Homozygous INS gene promotor mutations may present with either PNDM or later onset autoantibody negative diabetes in childhood. This suggests that homozygous INS gene promotor mutations show marked heterogeneity in clinical presentation within individuals in the same family. The pathophysiology of this is not well known but could be related to a number of factors, including the position of the variant, penetrance, other associated genetic defects, HLA etc. Premarital screening and genetic counselling is recommended for highly consanguineous families to reduce occurrence of such conditions.