Far be it from us to tell 23andMe how to run its business, but if it or any other DNA company wants to give customers a better read of disease risk, they might start asking how mom’s pregnancy went.
That’s the key message of a schizophrenia study, published [May 28], which showed that 108 regions of the genome previously identified as raising the risk of schizophrenia do so only slightly if the mother experiences no complications during pregnancy — but by some twelvefold if she does.
Taking into account prenatal conditions gives a starkly different read of how risky schizophrenia risk genes are: Taken together, they raise the chance of developing the disease to 12 in 1,000 if there are no complications — or to 80 in 1,000 if there are.
The idea that both genes and environment affect risk of disease is conventional scientific wisdom. But that usually means that while both genes and environment are involved, they act via separate biological pathways. BRCA mutations can raise the risk of breast cancer, for instance, and so can not bearing children, but the two don’t work by the same molecular mechanism.
23andMe doesn’t disagree. The company’s disease-risk analyses emphasize that, with the exception of single-gene disorders such as Huntington’s, you can have disease genes yet not develop the disease, or develop a disease despite not having the disease genes.
Read full, original post: Schizophrenia ‘risk genes’ are not so risky if the mother’s pregnancy was healthy