The diagnosis of fetal triploidy should be considered when there is a very high maternal serum alpha-fetoprotein and no ultrasound evidence of open neural tube defect, ventral wall defect, or any other explanation.
Our results support the hypothesis that mutations in the gene for PAX3 can predispose to NTD, but also show that, in general, mutations within or near the conserved domains of the PAX3 protein are only very infrequently involved in familial NTD.
The observation that the PAX3 homozygote in humans may allow life at least in early infancy and does not cause neural tube defects was unexpected, since, in all the mutations known in mice (splotch), homozygosity has led to severe neural tube defects and intrauterine or neonatal death.
Seventeen US families and 14 Dutch families with more than one affected person with NTD were collected and 194 people (50 affected) from both data sets were genotyped using the PAX3 polymorphic marker.
It has several possible causes: heterozygosity for rare loss of function mutations in the genes for 5,10-methylene tetrahydrofolate reductase (MTHFR) or cystathionine-beta-synthase (CBS); dietary insufficiency of vitamin co-factors B6, B12 or folates; or homozygosity for a common 'thermolabile' mutation in the MTHFR gene which has also been associated with vascular disease and NTDs.
We discuss the possibility that a mild deficiency of methionine synthase activity could be associated with mild hyperhomocysteinemia, a risk factor for cardiovascular disease and possibly neural tube defects.
In addition, they suggest directly that mutations in methionine synthase can lead to elevated homocysteine, implicated both in neural tube defects and in cardiovascular diseases.
It has several possible causes: heterozygosity for rare loss of function mutations in the genes for 5,10-methylene tetrahydrofolate reductase (MTHFR) or cystathionine-beta-synthase (CBS); dietary insufficiency of vitamin co-factors B6, B12 or folates; or homozygosity for a common 'thermolabile' mutation in the MTHFR gene which has also been associated with vascular disease and NTDs.
It has several possible causes: heterozygosity for rare loss of function mutations in the genes for 5,10-methylene tetrahydrofolate reductase (MTHFR) or cystathionine-beta-synthase (CBS); dietary insufficiency of vitamin co-factors B6, B12 or folates; or homozygosity for a common 'thermolabile' mutation in the MTHFR gene which has also been associated with vascular disease and NTDs.
The thermolabile variant of methylenetetrahydrofolate reductase (MTHFR) is not a major risk factor for neural tube defect in American Caucasians. The NTD Collaborative Group.
The thermolabile variant of methylenetetrahydrofolate reductase (MTHFR) is not a major risk factor for neural tube defect in American Caucasians. The NTD Collaborative Group.
In contrast to previous reports, we found the same distribution in fetuses with NTD and controls, which suggests that the MTHFRC677T mutation cannot be regarded as a genetic risk factor for NTD.
Although the 677C-->T mutation in the 5,10-methylenetetrahydrofolate reductase (MTHFR) gene is a risk factor for NTDs, it only partly explains the elevated homocysteine levels in mothers of children with NTDs.