The authors describe a 16-month-old infant presenting with neurologic developmental regression, severe pancytopenia, excessive skin pigmentation, and tremor resulting from nutritional vitamin B12 ...

A study found that B12 requirements may be too low for some people, putting them at risk for cognitive decline.

Pancytopenia is defined as low levels of all ... is less common than vitamin B 12 and folate deficiencies but can be associated with similar findings in peripheral-blood and bone marrow–biopsy ...