Hyperhomocysteinemia and Neurologic Disorders: a Review

Abstract

Homocysteine (Hcy) is a sulfur-containing amino acid that is generated during methionine metabolism. It has a physiologic role in DNA metabolism via methylation, a process governed by the presentation of folate, and vitamins B6 and B12. Physiologic Hcy levels are determined primarily by dietary intake and vitamin status. Elevated plasma levels of Hcy (eHcy) can be caused by deficiency of either vitamin B12 or folate, or a combination thereof. Certain genetic factors also cause eHcy, such as C667T substitution of the gene encoding methylenetetrahydrofolate reductase. eHcy has been observed in several medical conditions, such as cardiovascular disorders, atherosclerosis, myocardial infarction, stroke, minimal cognitive impairment, dementia, Parkinson's disease, multiple sclerosis, epilepsy, and eclampsia. There is evidence from laboratory and clinical studies that Hcy, and especially eHcy, exerts direct toxic effects on both the vascular and nervous systems. This article provides a review of the current literature on the possible roles of eHcy relevant to various neurologic disorders.

Biochemical and clinical effects of Whey protein supplementation in Parkinson's disease: A pilot study

“…Hcy is a known factor that mediates neurotoxicity. It induces oxidative stress in neurons and triggers neuronal cell death both in vitro and in vivo PD models [51,52]. A positive correlation between hyperhomocysteinemia and the HY scale was also demonstrated in PD patients treated with levodopa [53].…”

CerefolinNAC Therapy of Hyperhomocysteinemia Delays Cortical and White Matter Atrophy in Alzheimer’s Disease and Cerebrovascular Disease

“…HHcy is associated with a wide variety of neurological disorders including stroke, Parkinson's disease, and multiple sclerosis [4]. Compared to subjects with normal homocysteine levels, HHcy also associates with poorer cognitive performance [5], and with relatively greater regional brain atrophy [6] and ischemic lesions (i.e., white matter hyperintensities, ischemia, or infarcts) [7].…”

Serum Vitamin B12, Homocysteine and Methylmalonic Acid Levels in Patients With Parenchymal Neuro-Behçet’s Syndrome

“…22 Homocysteine is known to be toxic for endothelial cells and has also been found to be associated with lower cognitive scores and neurological disorders. 23,24 There are some potential weaknesses of this study. First, the number of patients was low.…”