When moms smoke, certain kids are more ...( a gene called glutathione S-transferase...),Health

This gene occurs in two common forms in the population-either present or null. Differences between present and null genes are small, but they mean a lot. When children are born with two of the null form of the gene, known as the GSTM1 null genotype, their bodies cannot produce the protective enzyme at all.

Among children in the study, more than 16 percent had a mother who smoked while the child was still in the womb. More than 45 percent of all children had the GSTM1 null variant genotype.

When researchers looked only at children with the GSTM1 null genotype, they found that in utero exposure to smoke was associated with increased prevalence of numerous respiratory symptoms:

3.7-fold risk increased risk for emergency room visits during the past year;
2.2-fold and 2.1-fold increased risks for wheezing with exercise and wheezing requiring medication, respectively;
80 percent increased risk for lifetime history of wheezing; and
70 percent and 60 percent increased risks for asthma with current symptoms and early onset asthma, respectively.

In contrast, researchers found no increased risk for respiratory problems among exposed children with the GSTM1 present genotype (at least one copy of the GSTM1 present allele).

Researchers warn that further studies are needed to confirm findings. The group hopes to examine links between other genes and respiratory disease risk. They already have shown that a variant in the glutathione S-transferase P1 gene is linked to decreased risk of respiratory illness-related school absences.

"Findings show that exposure to smoke in the womb for certain genetically susceptible chi
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Contact: Jon Weiner
Jonweine@usc.edu
323-442-2830
University of Southern California
16-Aug-2002