Measuring RNA expression from individual genes provides one route to novel insights in understanding human disorders such as autism. For example, it may reveal the impact of a genetic mutation on the gene itself or its indirect consequences on the expression of other genes.
Patterns of RNA expression can also help to define genetic networks and to reveal the effects of perturbing these systems. Applying network approaches over time can also inform us about the disorder and how it progresses.
The most appropriate tissue in which to study gene expression and networks is a frequently debated topic. As powerful new technologies generate seemingly endless streams of data, it has become clear that there is no single answer. The best source from which to draw meaningful conclusions about gene expression depends on the specific question being asked. And generalizing from one tissue to another inevitably involves appropriate caveats that must temper interpretation.