Monday, January 20, 2003
January 20, 2003 12:02:16 PM PST, Reuters
Some children are at greater risk than others for fetal alcohol syndrome if their mothers drink during pregnancy, and now a new genetic study provides one possible reason why. The study found that women with a certain form of an alcohol-processing gene were much more likely to give birth to a child with signs of fetal alcohol syndrome.
"Women with an alternate form of one of the genes responsible for alcohol metabolism, the ADH2-1/3 form, can metabolize more alcohol," the lead author of the study, Dr. Joan M. Stoler, told Reuters Health.
It is possible, Stoler said, that women with this form of the gene may be able to drink more, which could expose the fetus to higher levels of alcohol than women with another form of the gene.
"These findings give us one potential reason for why some women who drink heavily have babies which have more fetal effects than others who drink the same amount," said Stoler, who is at Massachusetts General Hospital in Boston.
A report on the study was published in a recent issue of the Journal of Pediatrics.
Women who are pregnant or who are trying to conceive are discouraged from drinking because alcohol use during pregnancy can cause birth defects, including fetal alcohol syndrome, which is the leading non-genetic cause of mental retardation.
Although all women are recommended to abstain from alcohol when they are expecting, not everyone who abuses alcohol during pregnancy gives birth to a child with severe damage. Genes involved in processing alcohol are suspected of influencing the effects of drinking during pregnancy, but the evidence is mixed.
Stoler's team studied 404 women who were considered at high risk of drinking during pregnancy to see which version of the ADH2 gene they had. The researchers were also able to classify the genes of 139 of these women's babies.
As expected based on previous studies, only a handful of white women--2%--had the gene version that allows a woman to metabolize more alcohol.
Surprisingly, though, 46% of African-American women had this version of the gene. The researchers had expected that about 33% of black women would have this form of the gene.
Women with this version of the gene were more likely to give birth to a child with signs of fetal alcohol syndrome, including facial defects and developmental delays. The risk of these effects was higher even when researchers took into account several other factors, including how much weight a woman gained during pregnancy or whether she smoked or abused drugs.
The gene variant may increase the risk that alcohol will affect a fetus by giving women a higher tolerance, allowing them to drink more, according to the report. Women with this version of the gene did drink more during pregnancy, although the difference was not statistically significant.
SOURCE: Journal of Pediatrics 2002;141:780-785.