VITAMIN B12 DEFICIENCY
Keywords:
Key words: B12- deficiency anemia, internal Castle factor, macrocytic anemia, methylmalonic acid, homocysteine.Abstract
Annotation. Vitamin B12 (B12; also known as cobalamin) is a B vitamin that
has an important role in cellular metabolism, especially in DNA synthesis, methylation
and mitochondrial metabolism. Clinical B12 deficiency with classic haematological
and neurological manifestations is relatively uncommon. However, subclinical
deficiency affects between 2.5% and 26% of the general population depending on the
definition used, although the clinical relevance is unclear. B12 deficiency can affect
individuals at all ages, but most particularly elderly individuals. Infants, children,
adolescents and women of reproductive age are also at high risk of deficiency in
populations where dietary intake of B12-containing animal-derived foods is restricted.
Deficiency is caused by either inadequate intake, inadequate bioavailability or
malabsorption. Disruption of B12 transport in the blood, or impaired cellular uptake
or metabolism causes an intracellular deficiency. Diagnostic biomarkers for B12
status include decreased levels of circulating total B12 and transcobalamin-bound
B12, and abnormally increased levels of homocysteine and methylmalonic acid. In this
research, we will discuss vitamin B12 deficiency, various diagnostic tests, and an
algorithm used in the investigation of vitamin B12 deficiency.
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