A hallmark of autism is impairment in reciprocal social interaction, including inadequate eye contact and failure to recognize emotions. Research shows that the neuropeptide oxytocin modulates social behavior. In mice, rats, monkeys and sheep, for instance, administration of oxytocin enhances social recognition, memory of peers, and development of partner preference and bonding. In people, including those with autism, oxytocin nasal spray can significantly enhance social cognition.

Perturbed neuronal arborization, or branching, and defects in long-range connectivity are likely to be shared mechanisms in many forms of severe autism. Neurotrophic factors (proteins that play a role in the growth and maintenance of neurons) and their cognate receptors, such as brain-derived neurotrophic factor (BDNF) and TrkB, respectively, govern the development of neuronal circuitry, in part, through signaling at the level of intracellular organelles known as endosomes. The protein NHE6 localizes within the cell membranes that form endosomes. Moreover, through its role in mediating the transport of protons (H+) out of endosomes in exchange for the import of sodium (Na+) ions, it contributes to modulating endosome acidity.

Several genes have been identified that contribute to the risk of developing autism spectrum disorders. Studies of infants at high risk (‘baby siblings’ of children with autism) have yielded exciting new findings about the earliest signs of the disorder, raising the hope that children could be diagnosed and therefore treated at an earlier age.

Autism spectrum disorder (ASD) is a heterogeneous group of neurodevelopmental disorders characterized by impairments in social interaction and communication, and restricted, stereotyped behaviors that manifest in early childhood. Research findings have identified widespread changes in the immune system in children with autism.

The chemical messenger serotonin has long been associated with autism. Serotonin is made in the blood and in the brain. In the brain, it is made by a specialized group of neurons in the brainstem and functions as a neurotransmitter, influencing the activity of neurons in virtually all regions. How abnormal serotonin function contributes to some of the key behaviors that define autism is not clear, but serotonin has been shown to affect the development and function of synapses, the junctions between brain cells. This is consistent with the idea that autism might be a disorder of the synapse.

The younger siblings of children diagnosed with autism are at an increased risk for autism themselves. By studying these at-risk babies, we can better understand the development of the condition and this, in turn, may lead to more effective early treatments. It remains challenging, however, to study brain function in a safe and effective way in young babies. Mark Johnson and his colleagues at the University of London have been developing a new method of brain imaging called functional near-infrared spectroscopy (fNIRS), which involves weak beams of light that are absorbed differently in active vs. inactive parts of the brain.

There is an immense need to find new treatments for children with autism. While some current therapies are effective, there is a lack of treatments that have a clear scientific basis. There is significant evidence to show that children with autism have decreased antioxidant defenses. This may lead to changes in the way cells function and contribute to the symptoms that children experience.

Some forms of autism spectrum disorder include stereotyped, repetitive motor behaviors. The cerebellum, a part of the brain that helps individuals to coordinate complex movements, appears to be physically altered in some people with autism. What’s more, several genes whose mutations have been linked to autism exert their actions strongly in the cerebellum. Together, these observations suggest that the electrical and chemical signals transmitted by neurons in the cerebellum may be disrupted, leading to some of the pathological motor behaviors associated with autism spectrum disorder.

Genotyping, gene expression and genetic sequencing methods are generating large amounts of data that are potentially relevant to autism research. Collaborative efforts and a searchable, web-based repository would maximally harness this unprecedented load of information. Giovanni Coppola’s team at the University of California, Los Angeles, has created a database of about 800,000 DNA sequence variants from roughly 900 individuals in the Simons Simplex Collection (SSC), which includes data and biospecimens from 2,700 families affected by autism. The database of sequence variants is intended for browsing and data mining by autism researchers worldwide.