Pernicious anemia causes
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Causes of Pernicious Anemia: An Overview
Autoimmune Gastritis and Intrinsic Factor Deficiency
Pernicious anemia (PA) is primarily caused by an autoimmune response that leads to chronic atrophic gastritis (CAG). This condition results in the destruction of the stomach's parietal cells, which are responsible for producing intrinsic factor (IF), a glycoprotein essential for vitamin B12 absorption Esposito2022Htut2021Lahner2009. The lack of intrinsic factor leads to vitamin B12 deficiency, which is the direct cause of pernicious anemia Castle1970Annibale2011.
Genetic Susceptibility
Genetic factors also play a significant role in the development of pernicious anemia. A genome-wide association study identified several genetic loci associated with an increased risk of PA, including PTPN22, PNPT1, HLA-DQB1, IL2RA, and AIRE genes . These genetic markers suggest that individuals with certain genetic backgrounds are more susceptible to developing the autoimmune conditions that lead to PA.
Autoimmune Disorders and Coexisting Conditions
Pernicious anemia is often associated with other autoimmune disorders, such as type 1 diabetes, vitiligo, and autoimmune thyroid diseases Lahner2009. This association underscores the autoimmune nature of PA and suggests a broader systemic predisposition to autoimmune conditions in affected individuals.
Helicobacter pylori Infection
Long-standing infection with Helicobacter pylori has been implicated in the pathogenesis of pernicious anemia. The infection can lead to chronic gastritis, which over time may evolve into an autoimmune process, resulting in the destruction of the gastric mucosa and subsequent intrinsic factor deficiency .
Diagnostic Challenges
Diagnosing pernicious anemia can be challenging due to its diverse clinical presentations and the limitations of current diagnostic tools. Patients may present with normal or even elevated serum cobalamin levels, making it difficult to identify the underlying deficiency Htut2021Oo2017Oo2019. Additionally, PA can mimic other hematological conditions, further complicating the diagnostic process Htut2021Oo2017.
Long-term Complications
If left untreated, pernicious anemia can lead to severe and potentially irreversible complications, including neurological damage and an increased risk of gastric cancer and type 1 gastric neuroendocrine tumors Esposito2022Murphy2015. Therefore, timely diagnosis and management are crucial to prevent these long-term consequences.
Conclusion
Pernicious anemia is a multifaceted disorder primarily caused by autoimmune gastritis leading to intrinsic factor deficiency and subsequent vitamin B12 deficiency. Genetic susceptibility, coexisting autoimmune disorders, and chronic Helicobacter pylori infection are significant contributing factors. The diagnosis of PA remains challenging due to its varied clinical presentations and the limitations of current diagnostic tests. Early recognition and treatment are essential to prevent serious long-term complications.
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