Autism and Schizophrenia Have Genetic Link
Researchers have been exploring any connections between autism, schizophrenia, and other mental disorders for several years, with the hope that each new discovery will bring them closer to understanding, preventing, and treating these conditions. Now new research from Tel Aviv University (TAU) reports that autism and schizophrenia appear to have a genetic link.
Autism and schizophrenia have common traits
Although autism spectrum disorder and schizophrenia may not look similar, they have some common traits, according to Dr. Mark Weiser, of TAU's Sackler Faculty of Medicine and the Sheba Medical Center. It's possible that those common characteristics, including social deficits, cognitive dysfunction, and difficulty functioning in the real world, have an underlying genetic thread.
To follow this thread, the investigators evaluated three data sets (one from Israel, two from Sweden) to identify any familial connection between the two disorders. To illustrate the wealth of information available to the researchers, the Israeli database alone contained information about more than one million individuals, including patients with autism and schizophrenia.
Analysis of all three data sets revealed the same results: individuals who have a sibling with schizophrenia are 12 times more likely to develop autism than people who have no schizophrenia in the family. The researchers also noted a similar relationship concerning siblings with bipolar disorder, but the risk was not as great.
Previous research on autism and schizophrenia
Much has been published concerning a connection between autism spectrum disorder, schizophrenia, and other mental disorders. In 2008, for example, two Canadian researchers proposed that the genes from a mother's egg and the father's sperm can impact whether a child's brain may develop toward autism or psychosis (e.g., schizophrenia), which are at opposite ends of the spectrum that includes a range of psychiatric and developmental brain disorders.
A 2011 study from Kings College London explored the neuroanatomy of autism spectrum disorders and schizophrenia by reviewing 33 studies that has used fMRI (functional magnetic resonance imaging) to compare individuals with autism or schizophrenia. They reported that while both conditions shared features concerning social cognition deficits, there also were some specific differences.
In a recent study published in Nature, it was noted that the age at which a man fathers children has an impact on how many mutations the offspring will inherit. That means children born to an older father have a greater chance of developing autism, schizophrenia, and other conditions associated with new mutations.
What the new TAU study means
The finding of this new study adds critical information to the growing literature on the role of genetics in autism spectrum disorder, schizophrenia, and other mental disorders. Weiser noted that understanding the genetic thread between autism and schizophrenia offers scientists a new direction for research.
Callaway E. Fathers bequeath more mutations as they age. Nature 2012 Aug; 488(439). doi:10.1038/488439a
Crespi B, Badcock C. Psychosis and autism as diametrical disorders of the social brain. Behavioral and Brain Sciences 2008 Jun; 31(3): 241-61
Sugranyes G et al. Autism spectrum disorders and schizophrenia: meta-analysis of the neural correlates of social cognition. PLoS One 2011; 6(10): e25322
Tel Aviv University