Jane C. Hu presents new research that found “autism is 55 percent heritable,” which is higher than previously thought:
The most surprising finding in this study is that the genetic risk for autism lies mostly in variations of common genes, and not specific mutations. A small mutation in a single gene can cause a disease such as Huntington’s, and mutation of the BRCA1 gene increases a woman’s chance of developing breast cancer. These sorts of mutations account for only 2.6 percent of autism risk, according to the new PAGES study, compared with 52 percent accounted for by common genes. In the vast majority of cases of autism, there is no one errant gene that codes for the disease, but rather a combination of common variations predicts autism risk. “You get a lot of the bad side of the coin and eventually push you into a disease,” says [Kathryn Roeder, a Carnegie Mellon University statistics and computational biology professor who led the study].
Our understanding of schizophrenia is also improving:
It took 80,000 genetic samples, seven years and the work of 300 scientists from around the world, but scientists now have the most complete dossier on schizophrenia ever. In an historic paper published in the journal Nature, the Schizophrenia Working Group of the Psychiatric Genomics Consortium identified 108 new regions on the genome linked to the psychiatric disorder, which is associated with hallucinations and psychotic episodes and affects about 1% of people worldwide.
Tom Insel, director of the National Institute of Mental Health, is excited about this research:
It may seem as if psychiatric genetics has gone from too few clues to too many. In fact, these new findings in schizophrenia and autism place these disorders squarely in the field of complex genetic disorders, disorders in which scores or hundreds of variants, both common and rare, contribute to risk. This recent progress is indeed a giant step forward for the field, but it is one step on a long journey. In truth, we do not have a rapid means to pivot from a genomic association to a target for treatment development. And complex genetic disorders, by definition, will not yield a simple genetic test for diagnosis. But these findings do suggest a way forward. By identifying the molecular pathways of risk, using cell-based studies with those pathways manipulated, and filling in the gap between molecular neuroscience and brain function, these new findings become part of the foundation for translational science.
The Dish 