DIABETES MELLITUS AND HEREDITY: THE ROLE OF GENETIC FACTORS

Аннотация

Diabetes mellitus (DM), encompassing type 1 (T1D) and type 2 (T2D), is a complex disease influenced by genetic and environmental factors. This article explores the hereditary basis of DM, focusing on key genetic variants, their mechanisms, and clinical implications. T1D is strongly linked to HLA genes, while T2D involves multiple loci, notably TCF7L2. Epigenetic modifications and gene- environment interactions further modulate disease risk. Advances in genetic research offer opportunities for early diagnosis and personalized treatment, but ethical challenges must be addressed. This review underscores the critical role of genetics in DM and highlights future directions for precision medicine. Keywords: Diabetes mellitus, type 1 diabetes, type 2 diabetes, genetics, heredity, HLA, TCF7L2, epigenetics, genome-wide association studies, personalized medicine. Diabetes mellitus (DM) is one of the most pressing global health challenges, affecting millions worldwide. Its primary forms, type 1 diabetes (T1D) and type 2 diabetes (T2D), differ in their pathophysiological mechanisms, yet both are significantly influenced by genetic factors. Advances in genetic research over recent decades have elucidated the hereditary basis of DM, identifying key genetic variants and their interactions with environmental factors. This article provides a comprehensive exploration of the genetic underpinnings of diabetes, emphasizing the role of heredity and its clinical implications. Both T1D and T2D are polygenic disorders, meaning their development involves the interplay of multiple genetic variants and environmental influences. T1D is primarily an autoimmune condition where the immune system destroys insulin-producing beta cells in the pancreas. T2D, in contrast, is characterized by insulin resistance and progressive beta-cell dysfunction. Genetic predisposition plays a critical role in both types. For instance, first-degree relatives of individuals with T1D have a 10–15-fold higher risk of developing the disease compared to the general population. In T2D, the concordance rate among monozygotic twins ranges from 70–90%, underscoring the significant hereditary component. 58 THEORETICAL ASPECTS IN THE FORMATION OF PEDAGOGICAL SCIENCES International scientific-online conference Genetic studies have identified numerous loci associated with DM. In T1D, the human leukocyte antigen (HLA) complex is the most significant genetic contributor. Polymorphisms in HLA-DR and HLA-DQ genes substantially increase T1D risk, particularly in Western populations, with HLA-DR3 and HLA-DR4 alleles showing strong associations. These genes regulate immune responses and contribute to autoimmune processes targeting beta cells. Beyond HLA, genes such as INS (insulin gene), CTLA4, PTPN22, and IL2RA have also been implicated in T1D susceptibility, influencing immune regulation, autoantibody production, and cellular signaling. T2D genetics is more complex, driven by the cumulative effect of multiple genetic variants with modest individual impacts. Genome-wide association studies (GWAS) have identified over 100 loci linked to T2D. The TCF7L2 gene is the most strongly associated, with its rs7903146 polymorphism significantly increasing T2D risk in European and Asian populations. TCF7L2 regulates insulin secretion and beta-cell function. Other notable genes include PPARG, KCNJ11, FTO, and IRS1, which are involved in insulin signaling, lipid metabolism, and obesity. The FTO gene, for instance, is associated with obesity risk, indirectly contributing to T2D susceptibility. Epigenetic modifications, such as DNA methylation, histone modification, and microRNA regulation, further complicate the hereditary landscape of DM. These mechanisms can modulate gene expression in response to environmental factors. For example, poor nutrition or stress during the intrauterine period can induce epigenetic changes that affect beta-cell function, increasing DM risk in subsequent generations—a phenomenon termed “metabolic memory.” This highlights the interplay between genetics and environment in DM pathogenesis. The clinical relevance of genetic factors extends beyond risk prediction to personalized medicine. Pharmacogenomics research has begun to uncover genetic determinants of treatment response in T2D, such as to metformin or sulfonylureas. Genetic screening also enables early identification of individuals at high risk for T1D, facilitating preventive strategies. However, widespread genetic testing raises ethical concerns, including data privacy and potential discrimination, which must be addressed to ensure responsible implementation. Environmental factors, including lifestyle (diet, physical activity, stress), interact with genetic predisposition to drive DM development. Obesity, a major risk factor for T2D, amplifies the effects of genetic variants. Thus, effective prevention and management of DM require an integrated approach that considers both genetic and environmental factors.