The brains of people with autism have abnormally dense and stubby dendritic spines, the neuronal projections that receive electrical signals, according to data presented Monday at the Society for Neuroscience annual meeting in San Diego.

Mice missing a large protein at the junction between neurons show motor impairments, anxiety and increased social behaviors, according to a study in the American Journal of Psychiatry. The protein, postsynaptic density-95 or PSD-95, is part of a key molecular bridge connecting other proteins linked to autism.

A new study, published in September in PLOS Genetics, shows the importance of comparing cases to controls when linking mutations to a disorder. The researchers propose a new method of analysis that takes into account the large size of many genes expressed in the brain.

Scientists have discovered that neurexins — proteins linked to autism — bind to a wide variety of molecules at the junction between neurons. In this complicated system, the breakdown of any one of the parts could lead to improper cell signaling, ultimately giving rise to disease.

Several independent groups have found previously unknown risk genes for autism, schizophrenia and mental retardation. The candidate genes have one thing in common: they encode proteins that are needed for the healthy function of synapses, the junctions between neurons.

Variations in two genes needed to form connections between brain cells may be associated with autism spectrum disorder, according to a study published 25 March in Molecular Autism. Some variants in the genes seem to increase susceptibility to autism, whereas others protect children from developing the disorder.

Several studies in the past year in people, mice and honeybees have tied autism to a protein that helps neurons communicate. Problems with the protein, neurexin 1, are associated with a wide range of autistic behaviors, such as impaired social interactions, anxiety and problems with learning and memory.

A chilling new technique shows the intricate and coordinated activity of previously mysterious pieces of the synapse, the all-important junction between neurons that allows cells to talk to each other.

Rare mutations that increase the risk of neuro-psychiatric diseases usually occur in only one copy of a gene. What happens when both copies are mutated?

Scientists have identified several autism-specific variants in a gene that lies within a chromosomal region linked to the disorder, according to a poster presented at the World Congress of Psychiatric Genetics in San Diego.