A patient presents with chronic fatigue, peripheral neuropathy, and glossitis despite consuming adequate iron. Which mechanism explains these symptoms in the context of B12 deficiency?

💡 Explanation

B12 is crucial for DNA synthesis, especially in rapidly dividing cells like those in the bone marrow and gastrointestinal tract. A deficiency leads to ineffective hematopoiesis and neurological issues due to impaired myelin synthesis because methylmalonyl-CoA mutase requires B12. Therefore, impaired DNA synthesis explains the symptoms, rather than erythropoietin or hepcidin affecting iron.

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