Difference in type 1 and type 2 diabetes
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Differences Between Type 1 and Type 2 Diabetes
Genetic Susceptibility and Family History
Type 1 and type 2 diabetes often co-occur within the same families, indicating a shared genetic susceptibility. This mixed family history can result in an intermediate diabetes phenotype, characterized by insulin resistance and cardiovascular complications in type 1 diabetes patients, and lower BMI and fewer cardiovascular complications in type 2 diabetes patients. Additionally, genetic markers such as HLA and insulin gene characteristics are more prevalent in type 2 diabetes patients with a mixed family history, especially those who are GAD antibody-positive.
Pathophysiology and Disease Progression
Type 1 diabetes (T1D) is primarily caused by an autoimmune response that leads to the destruction of insulin-producing beta cells in the pancreas, resulting in inadequate insulin production. In contrast, type 2 diabetes (T2D) is mainly due to insulin resistance, where the body's cells do not respond effectively to insulin, often accompanied by inadequate insulin secretion. Both types of diabetes can involve a combination of these mechanisms, but the rate at which beta cell function is lost varies, with T1D typically progressing faster than T2D.
Clinical Presentation and Diagnosis
Distinguishing between type 1 and type 2 diabetes can be challenging, especially in adults who may present with features of both types. Classic type 1 diabetes often presents in younger individuals with rapid onset of symptoms such as polyuria, polydipsia, and weight loss, whereas type 2 diabetes typically presents in older adults with a more gradual onset and is often associated with obesity . However, increasing obesity rates and the recognition of type 1 diabetes in older adults blur these distinctions.
Metabolic and Coagulatory Differences
Early metabolic abnormalities differ between type 1 and type 2 diabetic polyneuropathy (DPN). Type 2 diabetes tends to have milder initial functional defects despite similar hyperglycemic exposures, while type 1 diabetes shows more severe late structural changes, including progressive axonal atrophy and paranodal degenerative changes. Both types of diabetes lead to coagulatory defects, but the mechanisms differ, affecting haemostasis through altered concentrations of coagulatory proteins, platelet hyperactivation, and endothelial dysfunction.
Genetic Overlap and Divergence
Research has identified genetic regions associated with both type 1 and type 2 diabetes, suggesting a complex genetic relationship. Some genetic variants affect the risk of both diseases, but often in opposite directions, indicating divergent genetic mechanisms. For example, variants near the GLIS3 gene increase the risk for both types of diabetes, while other regions show opposite effects on disease risk.
Conclusion
While type 1 and type 2 diabetes share some genetic and phenotypic characteristics, they differ significantly in their pathophysiology, clinical presentation, and metabolic impacts. Understanding these differences is crucial for accurate diagnosis and effective management of both types of diabetes.
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