Men born with a birth defect have a substantially increased risk of having a child with a birth defect, a large population study revealed today. Compared with other fathers, the risk was doubled.
The second-generation risk also appeared higher - at least for dissimilar birth defects - than for the offspring of mothers who had been born with birth defects.
Scientists at the U.S. National Institute of Environmental Health Sciences and Norway's University of Bergen reviewed Norwegian births since 1967. They compared 12,000 men who had been born with a recognized defect with nearly a half-million unaffected men. The scientists reported today in the Journal of the American Medical Association for Feb. 14 that the men had fathered 1,265 children and that:
Twenty-one of these children (1.6 percent) had been born with the same defect as their father's. This is about seven times the risk of those same defects in the general population but is about the same risk as a previous study showed for the children of women with birth defects.
However, the children of fathers with birth defects also had a higher risk of having different, unrelated birth defects. Forty-three children (3.4 percent) had defects that were not like their father's, compared to an expected number of 24 (1.9 percent). This result was in contrast to the findings of the previous women's study in which the children of women with defects appeared to have no increased risk of babies with defects different from the mother's.
The total risk of birth defects was 5.1 percent among the offspring of fathers with defects, or twice the 2.1 percent risk of the offspring of other fathers. The risk was spread out across categories of defects, not concentrated in any one category.
"Five percent of children with birth defects is not a whole lot," Allen J. Wilcox, M.D., Ph.D., said, "but it still is more than double what we see in the children of unaffected fath
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Contact: Bill Grigg
grigg@niehs.nih.gov
301-402-3378
NIH/National Institute of Environmental Health Sciences
13-Feb-2001