Fragile X syndrome is the most common cause of inherited autism and results from loss of function of a single gene: FMR1. Most research into the pathogenesis of fragile X syndrome has focused on the role of FMRP, the protein encoded by FMR1, in neuronal health and function. However, recent work in cultured cells suggests that loss of FMR1 in astrocytes, star-shaped brain cells that help support neurons at their junctions (synapses), can contribute to the abnormal dendritic morphology and synapse development seen in fragile X. In addition, over the past decade, increasing evidence has demonstrated that glia — support cells in the brain — such as astrocytes play important roles in regulating neuronal synaptic development, plasticity and communication. These are activities that, if altered, may contribute to fragile X syndrome and autism.

Finding a way to diagnose autism early in development is crucial for devising new interventions and understanding its underlying neurobiological causes. It is, however, difficult to detect characteristic deviations in behavior or brain function in infants and toddlers. Measuring pupil size may be the right tool. The test is noninvasive, quick and easy to use, even in newborn infants. It is also surprisingly revealing of complex brain processes.

Human brain function is the result of a highly organized network of connections linking multiple areas across the brain. A popular theory to explain autism is that genetic variants interact with environmental factors and lead to impaired or dysfunctional communication between these unique brain areas. However, the genetic and neurobiological determinants of the connectivity impairments observed in autism are largely unknown.

Nerve cells communicate with each other via excitatory and inhibitory signals. Growing evidence supports the hypothesis that a neuronal excitation/inhibition imbalance resulting in increased excitation in certain nerve cells in the brain is sufficient to elicit autism-like symptoms. Uwe Rudolph and his colleagues at McLean Hospital and Harvard Medical School focus on receptors for the major inhibitory neurotransmitter in the central nervous system, gamma-aminobutyric acid (GABA).

A small protein called ubiquitin is added to other proteins to modify their function, causing changes in cellular behavior. Often, the addition of ubiquitin leads to the complete destruction of the tagged protein. This process, called ubiquitination, plays an important role in regulating the abundance of many proteins at neuronal junctions, or synapses, including receptors within the postsynaptic density (a brain region that contains receptors and other proteins that regulate neuronal function).

Advances in structural magnetic resonance imaging (MRI) offer improved ability to detect subtle abnormalities in brain architecture. MRI biomarkers for brain pathology in autism have been notoriously difficult to establish. Although this may be due to limitations in MRI technology, it may also result from combining individuals with diverse genetic and environmental factors that contribute to their autism.

Over the past few years, studies have linked many genes to autism. With these discoveries comes the possibility of developing therapeutic approaches, but where to start? Alex Parker and his colleagues at the Centre Hospitalier de l’Universite de Montreal hope to use the worm C. elegans to find molecules that may be early drug development leads to help treat autism spectrum disorders.

Recent discoveries of contrasting phenotypes caused by deletion vs. duplication events within the same genetic locus suggest that investigation of gene dosage effects may provide valuable clues into how copy number variations (CNVs), or duplications or deletions of stretches of DNA, disrupt the brain and ultimately contribute to disease pathogenesis. However, almost nothing is known about the consequences of such reciprocal imbalances on brain function or behavior.

Between one-third and one-half of individuals with autism display repetitive, self-injurious behavior, ranging from head banging to self-directed biting and punching. In cases of treatment-resistant self-injurious behavior, electroconvulsive therapy (ECT) can produce life-changing results, with more than 90 percent suppression of self-injurious behavior.