Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:1.5.7.1 (methylenetetrahydrofolate reductase)
 2,116 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Polymorphisms in genes can lead to differences in the level of susceptibility of individuals to potentially adverse effects of environmental influences, such as chemical exposure, on prenatal development or male or female reproductive function. We have reviewed the literature in this area, with the caveat that papers involving straight gene knock-outs in experimental animals, without a clear human relevance, were largely excluded. This review represents current knowledge in this rapidly moving field, presenting both human epidemiological and animal data, where available. Among the polymorphic genes and environmental interactions discussed with respect to prenatal development are those for P-glycoprotein (multidrug resistance protein) and the avermectins; methylenetetrahydrofolate reductase (MTHFR), an enzyme in folate metabolism, and dietary folic acid; transforming growth factor alpha (TGFalpha) and cigarette smoke; and alcohol dehydrogenase (ADH) and cytochrome P-450 (CYP) 2E1 in association with alcohol consumption. Effects on male reproduction attributable to gene-environment interaction involve infertility seen as a result of either organophosphorous (OP) pesticide interaction with the polymorphic paraoxonase (PON1) gene or antiandrogenic agent interaction with the androgen receptor (AR). MTHFR, folate metabolism, and dietary folic acid are also considered in conjunction with preeclampsia and early pregnancy loss, and the effect of the interaction of glutathione S-transferase (GST) with exposure to benzene or cigarette smoke on pregnancy maintenance is explored. As a conclusion, we offer a discussion of lessons learned and suggested research needs.
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PMID:Gene-environment interactions: a review of effects on reproduction and development. 1560 83

The causes of spermatogenetic failure found in most cases of non-ohstmctive azoospermia or severe oligospermia remain largely unclear. It is estimated that in about 30% of the cases, male infertility is due to genetic causes, including chromosomal abnormalities, Y chromosome microdeletions, gene mutations, etc. Klinefelter's syndrome and microdeletions in the Y chromosome long arm (Yq) represent the most frequent molecular genetic cause of severe infertility. Gene mutations involved in male infertility include the cystic fibrosis transmembrane conductance regulator (CFTR) gene, androgen receptor (AR) gene, insulin-like factor 3 (INSL3) gene and leucine-rich repeat-containing G-protein coupled receptor 8 (LGR8) gene. CFTR mutations cause cystic fibrosis, absence of vas deferens and non-obstructive azoospermia. The AR gene mutations are responsible for the androgen insensitivity syndrome and spermatogenetic damage. And INSL3 and LGR8 gene mutations have been associated with abnormalities in testis descent and cryptorchidism. Meta-analyses have revealed a significant association between the polymorphism and male infertility only for partial AZFc deletion, CAG repeat length in the AR gene and methylenetetrahydrofolate reductase (MTHFR) gene. This paper mainly reviews the genetic causes of male infertility and the genetic polymorphisms possibly associated with male infertility.
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PMID:[Genetic causes of male infertility]. 1900 17