Testicular MTHFR protein levels decreased significantly in wild-type mice on the 20× diet but not in those on the 10× diet, suggesting a possible role for MTHFR deficiency in sperm DNA hypomethylation.
Five patients suspected of having non-classical homocystinuria due to MTHFR deficiency were examined with respect to their symptoms, MTHFR enzyme activity and genotypes of the MTHFR gene.
The diagnosis of MTHFR deficiency was confirmed based on extremely reduced fibroblast MTHFR activity (0.3 nmol CHO/mg prot/hr) as well as mutation analysis that revealed two variants in the MTHFR gene, a splice site mutation p (IVS5-1G>A), as well as a missense mutation (c.155 G>A; p. Arg52Gln).
In earlier work, we isolated the human cDNA for MTHFR, and reported 14 mutations in severe MTHFR deficiency, as well as a common 677C-->T missense mutation (Ala-->Val) that encodes the thermolabile MTHFR.
These results underscore the importance of folate interconversion in VPA-induced teratogenicity, since VPA increases MTHFR expression and has lower teratogenic potential in MTHFR deficiency.
Seven novel mutations in the methylenetetrahydrofolate reductase gene and genotype/phenotype correlations in severe methylenetetrahydrofolate reductase deficiency.
The biochemical features in these four subjects are distinguishable from subjects homozygous for the thermolabile MTHFR, whose specific activity is approximately 50% of the normal mean, and from heterozygotes for severe MTHFR deficiency, in whom the enzyme is thermostable and has a specific activity of about 50% of the normal mean.
A common variant in methylenetetrahydrofolate reductase (MTHFR677C→T) causes mild MTHFR deficiency with lower 5-methyltetrahydrofolate for methylation reactions.
In the latter group, remethylation disorders of homocysteine to methionine (chiefly CblC defect and 5,10-methylenetetrahydrofolate reductase [MTHFR] deficiency) are by far the most frequently encountered situations.
The ongoing identification and characterisation of mutations in the MTHFR gene will provide further insight into the heterogeneity of the clinical phenotype in severe MTHFR deficiency.
Conserved vitamin D-responsive element (VDRE)-type sequences in the Bhmt1 and Ikzf2 promoters, the universal need for methionine in epigenetic regulation, and betaine's protective effects in MTHFR-deficiency suggest similar regulatory mechanisms exist in humans.
The combination of MTHFR deficiency and HFAT exacerbates changes in inflammatory mediators and introduces additional effects on inflammation (Saa2) and lipid metabolism (Nr1h4, Srebf1c, Ppara, and Crot).
The combination of MTHFR deficiency and HFAT exacerbates changes in inflammatory mediators and introduces additional effects on inflammation (Saa2) and lipid metabolism (Nr1h4, Srebf1c, Ppara, and Crot).
Treatment with Mefolinate (5-Methyltetrahydrofolate), but Not Folic Acid or Folinic Acid, Leads to Measurable 5-Methyltetrahydrofolate in Cerebrospinal Fluid in Methylenetetrahydrofolate Reductase Deficiency.