Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0030567 (Parkinson's disease)
 63,064 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Elevated concentration of total homocysteine (Hcy) in plasma (> 12 micromol/l) is a risk factor for several diseases of the central nervous system. Epidemiological studies have shown a dose-dependent relationship between concentrations of Hcy and the risk for neurodegenerative diseases. Hcy is a marker for B-vitamin deficiency (folate, B12, B6). Hyperhomocysteinemia (HHcy) causes hypomethylation which is an important mechanism that links Hcy to dementia. Supplementation with vitamins B aims at reducing the risk of neurodegenerative diseases. Current evidence suggests that Hcy-lowering treatment has a positive effect for the secondary and primary prevention of stroke. HHcy is very common in patients with Parkinson disease particularly those who receive L-dopa treatment. Furthermore, a positive association has been reported between HHcy and multiple sclerosis. Moreover, HHcy and vitamin B deficiency are reported to have a causal role in depression, and epilepsy. In addition several anti-epileptic drugs cause secondary HHcy. Therefore, sufficient intakes of the vitamins are recommended for patients who have already developed neuropsychiatric diseases. Vitamin B deficiency should be suspected in children with development disorders, failure to thrive and unexplained neurological manifestations. Elderly people are also an important at-risk group where vitamin B deficiency and HHcy have been linked to neurodegenerative diseases. Treatment with folate, B12, and B6 can improve cerebral function. Preventive vitamin B supplementation and sufficient intake seem very important for secondary and primary prevention of neuropsychiatric disorders, especially in subjects with a low intake or status of the vitamins.
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PMID:[Review of the role of hyperhomocysteinemia and B-vitamin deficiency in neurological and psychiatric disorders--current evidence and preliminary recommendations]. 1772 91

Neurodegenerative diseases are the diseases of the central nervous system with various aetiology and symptoms. Dementia, Alzheimer's disease (AD), Parkinson's disease (PD) and autism are some examples of neurodegenerative diseases. Hyperhomocysteinemia (Hhcy) is considered to be an independent risk factor for numerous pathological conditions under neurodegenerative diseases. Along with genetic factors that are the prime cause of homocysteine (Hcy) imbalance, the nutritional and hormonal factors are also contributing to high Hcy levels in the body. Numerous clinical and epidemiological data confirm the direct correlation of Hcy levels in the body and generation of different types of central nervous system disorders, cardiovascular diseases, cancer and others. Till now, it is difficult to say whether homocysteine is the cause of the disease or whether it is one of the impacts of the diseases. However, Hhcy is a surrogate marker of vitamin B deficiency and is a neurotoxic agent. This Mini Review will give an overview of how far research has gone into understanding the homocysteine imbalance with prognostic, causative and preventive measures in treating neurodegenerative diseases.
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PMID:Hyperhomocysteinemia: Impact on Neurodegenerative Diseases. 2603 86

Homocysteine (Hcy), a sulfur-containing nonproteinogenic amino acid, is generated as a metabolic intermediate. Hcy constitutes an important part of the "1-carbon metabolism" during methionine turnover. Elevated levels of Hcy known as hyperhomocysteinemia (HHcy) results from vitamin B deficiency, lack of exercise, smoking, excessive alcohol intake, high-fat and methionine-rich diet, and the underlying genetic defects. These factors directly affect the "1-carbon metabolism (methionine-Hcy-folate)" of a given cell. In fact, the Hcy levels are determined primarily by dietary intake, vitamin status, and the genetic blueprint of the susceptible individual. Although Hcy performs an important role in cellular functions, genetic alterations in any of the key enzymes responsible for the "1-carbon metabolism" could potentially upset the metabolic cycle, thus causing HHcy environment in susceptible people. As such, HHcy relates to several clinical conditions like atherosclerosis, myocardial infarction, stroke, cognitive impairment, dementia, Parkinson's disease, multiple sclerosis, epilepsy, and ocular disorders, among others. This article summarizes the findings from our laboratory and public database regarding genetics of HHcy and its effects on ocular disorders, their respective management during dysregulation of the 1-carbon metabolism.
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PMID:Genes and genetics in hyperhomocysteinemia and the "1-carbon metabolism": implications for retinal structure and eye functions. 3136 12