Narrowing down gene and environment interactions in autism

With hundreds of genes, thousands of environmental factors, and now sex being variables in determining risk for autism, where should science start?  Over the decades researchers have been able to start narrowing down the combinations based on specific behaviors of interest, genes, and mechanisms which may narrow down which gene, which environmental factor and which sex.  Dr. Sara Schaafsma and Dr. Donald Pfaff from Rockefeller University combined the three, and found that epigenetic changes in an autism risk gene called contact in associated protein like 2 contributed to elevation of risk for autism behaviors following maternal infection.  In other words, being male and having the mutation produced small changes, increased by the environmental factor.  In another separate study, Dr. Keith Dunaway and Dr. Janine LaSalle at UC Davis used brain tissue to look at a rare variant for autism on chromosome 15.  Typically, mutations of this area of the genome are thought to cause autism.  However, the effects of these mutations are also increased when environmental factors are present, leading to more de novo mutations.  These are all examples of scientific breakthroughs that are helping better understand what causes autism.  Even when it looks like one thing, it’s multiple things.

Why is there a link between c-sections and autism?

Happy New Year!  Over the holiday break, a the largest study so far including the most number of countries analyzed the risk of having a c-section and autism.  They found a consistent increase risk that wasn’t due to cause of the c-section or the age of the infant (preemie or term).  So what is going on?  This week’s podcast warns against the unintended consequences of linking c-sections to autism and offers an explanation of the findings in addition to what the study authors provide.