Making and breaking serotonin neurons and autism.

Dysfunction of brain serotonin system development is hypothesized to contribute to autistic behaviors. The testing of this hypothesis will likely depend on a better understanding of the genes and mechanisms involved in serotonin neuron cell fate specification. In this review we summarize the main features of vertebrate serotonin neuroanatomical development and recent studies that have revealed critical steps in the molecular genetic program that controls serotonin neuron phenotype. We then discuss the potential relevance of these findings to advances in autism research and to new molecular genetic tools under development that will impact future testing of the hypothesis.