View larger image | Projections called axons transmit messages from one nerve cell to another (left) at the synapse (right), a junction between nerve cells held in place with the aid of various cell-adhesion molecules. Studies have linked autism with mutations in a number of genes involved in cell adhesion at the synapse. A disruption in any one of the proteins (dark purple) that these genes code for may throw off the system so that nerve cells don’t connect normally. Credit: C. Betancur et al/Trends in Neurosciences, adapted by E. Feliciano