Autism Studies and Related Medical Conditions, January 2009 - TACA

esponse to folate deprivation. Expression of cystathione beta synthase followed
a similar pattern. By contrast, expression and activity of methionine synthase
decreased following folate deprivation in the order ApoE +/+ < ApoE +/- < ApoE
-/-. These studies demonstrate that folate deficiency induces compensatory
regulation of methionine cycle genes, and that these effects are potentiated by
ApoE deficiency in a gene-dosage manner. They further support the notion that
latent genetic deficiencies, including those of methionine cycle, may contribute to
Alzheimer's disease, especially in concert with age-related nutritional deficiencies.
PMID: 16910166 [PubMed - indexed for MEDLINE]
Ueland PM, Hustad S, Schneede J, Refsum H, Vollset SE. Biological and clinical
implications of the MTHFR C677T polymorphism. Trends Pharmacol Sci. 2001
Apr;22(4):195-201.
LOCUS for homocysteine and related vitamins, Armauer Hanssens hus, University
of Bergen, 5021, Bergen, Norway. per.ueland@ikb.uib.no
The enzyme methylenetetrahydrofolate reductase (MTHFR) directs folate species
either to DNA synthesis or to homocysteine (Hcy) remethylation. The common
MTHFR C677T polymorphism affects the activity of the enzyme and hence folate
distribution. Under conditions of impaired folate status, the homozygous TT
genotype has been regarded as harmful because it is associated with a high
concentration of plasma total Hcy, increased risk of neural tube defects and
colorectal neoplasias, and can also predispose individuals to adverse effects from
drugs with antifolate effects. The MTHFR C677T polymorphism shows no
consistent correlation with cardiovascular risk and longevity but, in combination
with positive folate balance, the TT genotype is associated with decreased risk of
colorectal neoplasias. Because of the high prevalence of this polymorphism in
most populations, the TT variant might represent an ancestral genetic adaptation
to living constraints (tissue injury or unbalanced vitamin intake) that has become
a determinant of disease profiles in modern times.
PMID: 11282420 [PubMed - indexed for MEDLINE]
Vancassel S, Durand G, Barthelemy C, Lejeune B, Martineau J, Guilloteau D, Andres C,
Chalon S. Plasma fatty acid levels in autistic children. Prostaglandins Leukot Essent
Fatty Acids. 2001 Jul;65(1):1-7.
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