In May two rival research groups discovered a genetic variant--make that a flaw--on chromosome 9 that may boost the risk of early heart attack by as much as 70%.

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But a subset of patients who did not have a genetic variant called APOE4, showed statistically significant improvements across four different tests for Alzheimer's symptoms, Wyeth and Elan said, when compared to a control group of patients who did not get the drug.

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In the third study, which also looked at children in New York City, researchers found that the association between organophosphate exposure and developmental delays was more pronounced in children whose mothers had a certain genetic variant that influences an enzyme that breaks down organophosphates.

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One interesting point about this observation is that it requires both a genetic input (the 7R variant) and an environmental one (the network of friends) to take effect.

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Autism and Asperger Syndrome (its (somewhat) less severe variant) are obviously genetic with incomplete penetrance and a heritability of 90%.

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