HYPERHOMOCYSTEINEMIA

Abstract

Homocysteine is a non-proteinogenic amino acid
and differs from cysteine by an additional methylene
bridge. It is synthesized from methionine and can be
recycled into methionine or converted into cysteine in
the presence of certain B vitamins (Figure 1).
Homocystinuria, a rare autosomal disorder characterized
by steep elevation of homocysteine in plasma
and urine, is always accompanied by systemic clinical
manifestations. On the contrary, hyperhomocysteinemia
is characterized by a less markedly elevated
level of homocysteine (above 15 μmol/L) in serum
measurements [1]. Hyperhomocysteinemia is more
common than homocystinuria and affects 5-7% of
the general population [2].