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Homocysteine

Meaning

Homocysteine is a non-proteinogenic amino acid that is an intermediate product in the cellular metabolism of the essential amino acid methionine, a process known as the methionine cycle. While it is a naturally occurring metabolite, elevated plasma levels, a condition called hyperhomocysteinemia, are recognized clinically as an independent risk factor for various vascular and neurodegenerative disorders. The clinical focus is on maintaining homocysteine within a healthy range, as its accumulation suggests deficiencies in critical B vitamins—specifically folate, B6, and B12—which are necessary cofactors for its breakdown or recycling.