Excess vitamin B12- why this occurs?

[ZEENAM]

Hello, my friend's vitamin B12 level is high. Hypercobalaminemia (high serum vitamin B12 levels) is a frequent and underestimated anomaly. Clinically, it can be paradoxically accompanied by signs of deficiency, reflecting a functional deficiency linked to qualitative abnormalities, which are related to defects in tissue uptake and action of vitamin B12. The aetiological profile of high serum cobalamin predominantly encompasses severe disease entities for which early diagnosis is critical for prognosis. These entities are essentially comprised of solid neoplasms, haematological malignancies and liver and kidney diseases. What is the pathophysiology behind this condition?

[TASMEEN]

@zeenam Vitamin B12 was discovered as the antipernicious anaemia factor that was found in the liver. The discovery, by two independent teams, of liver as a dietary factor that could reverse anaemia in pernicious anaemia patients led to the Nobel prize in 1934. In the 1930s, researchers started to attempt isolating the ‘active principle’ in liver that contained the antipernicious anaemia factor. In the mean time, the importance of gastric juice for inducing reticulocytosis in pernicious anaemia patients was identified. Only in 1947, two groups independently managed crystallizing the active principle. No other micronutrient than vitamin B12 is known to require a specific factor for its absorption. Without this absorption factor vitamin B12 deficiency follows. Only during the 1950s, this vitamin B12 absorption factor, called intrinsic factor (IF) as opposed to the extrisic factor (vitamin B12 itself) had been to some extent purified.