Construction of a high resolution linkage disequilibrium map to evaluate common genetic variation in TP53 and neural tube defect risk in an Irish population.

Genetic and environmental factors contribute to the etiology of neural tube defects (NTDs). While periconceptional folic acid supplementation is known to significantly reduce the risk of NTDs, folate metabolic pathway related factors do not account for all NTDs. Evidence from mouse models indicates that the tumor protein p53 (TP53) is involved in implantation and normal neural tube development.

Evaluation of transcobalamin II polymorphisms as neural tube defect risk factors in an Irish population.

Background: Decreased maternal folate levels are associated with having a child with a neural tube defect (NTD), and periconceptual folic acid supplementation reduces this risk by >50%. Vitamin B(12) (as methylcobalamin) is a cofactor for methionine synthase, an enzyme that plays a key role in folate metabolism. Alterations in vitamin B(12) metabolism may influence the development of NTDs.

Analysis of the human folate receptor beta gene for an association with neural tube defects.

The folate receptor beta (FRbeta) gene encodes a receptor that binds and transports 5-methyltetrahydrofolate. FRbeta polymorphisms may potentially alter folate delivery and are likely candidates for an association with neural tube defect (NTD) risk. To look for association between FRbeta polymorphisms we studied NTD-affected children and their parents (254 triads) recruited throughout Ireland and a control population of 296 pregnant women who did not give birth to an NTD-affected child.

Analysis of the MTHFR 1298A-->C and 677C-->T polymorphisms as risk factors for neural tube defects.

The thermolabile variant (677TT) of methylenetetrahydrofolate reductase (MTHFR) is a known risk factor for neural tube defects (NTDs). The relationship between a second MTHFR polymorphism (1298A-->C) and NTD risk has been inconsistent between studies. We genotyped 276 complete NTD triads (mother, father and child affected with an NTD) and 256 controls for MTHFR 1298A-->C.

A polymorphism, R653Q, in the trifunctional enzyme methylenetetrahydrofolate dehydrogenase/methenyltetrahydrofolate cyclohydrolase/formyltetrahydrofolate synthetase is a maternal genetic risk factor for neural tube defects: report of the Birth Defects Research Group.

Women who take folic acid periconceptionally reduce their risk of having a child with a neural tube defect (NTD) by >50%. A variant form of methylenetetrahydrofolate reductase (MTHFR) (677C-->T) is a known risk factor for NTDs, but the prevalence of the risk genotype explains only a small portion of the protective effect of folic acid. This has prompted the search for additional NTD-associated variants in folate-metabolism enzymes.