CNTNAP2 is a gene that encodes a member of the neurexin family of proteins and has been implicated in autism spectrum disorders. Neurexins function in the vertebrate nervous system as cell adhesion molecules and receptors. CNTNAP2 is expressed in the region where precursor cells of the neocortex (the outer layer of the brain) originate during embryogenesis, suggesting that it has a role in regulating neural stem cells.

Perturbations in the fundamental brain processes that underlie eye movement may be linked to the psychological and neural abnormalities seen in individuals with autism spectrum disorders. To test this hypothesis, researchers must be able to characterize eye movements of participants during behavioral tasks and in functional magnetic resonance imaging (fMRI) studies.

Ruth O’Hara and her colleagues at Stanford University investigated the types of sleep disorders that are most prevalent in autism. Their findings provide a clearer picture of sleep disorders associated with autism and, in turn, increase our knowledge of which treatments may be most effective at improving sleep in autism.

Copy number variants (CNVs) are segments of DNA that vary in copy number between different individuals. CNVs confer significant risk of neuropsychiatric disorders, including autism and schizophrenia. Notably, there appears to be a reciprocal relationship between copy number and brain size for certain genetic loci. For example, deletions of the genomic region 16p11.2 tend to be associated with autism and increased head circumference, whereas duplications of the same segment tend to be associated with schizophrenia and smaller head circumference. The contrasting clinical phenotypes that are associated with reciprocal changes in gene dosage could represent opposite extremes of the same neurodevelopmental process.

Autism is a syndrome with many causes. David Sulzer and his colleagues at Columbia University examined their new hypothesis that some of these processes converge during a developmental period from early childhood through adolescence when cortical synapses — the connections that provide for communication between neurons — lose approximately half of their overall density, a phenomenon known as ‘synaptic pruning.’

Copy number variations (CNVs), or altered numbers of certain stretches of DNA, have been implicated as a genetic cause of autism. Alea Mills and her colleagues at Cold Spring Harbor Laboratory in New York set out to determine whether CNVs in the chromosomal region 16p11.2 cause autism-like phenotypes. They used chromosome engineering to generate mice with a deletion corresponding to 16p11.2 — one of the most prevalent genomic lesions associated with autism — as well as mice with reciprocal duplication of this region.

New protein synthesis is essential for long-lasting memory, and regulation of neuronal translation by the ERK and mTOR signaling pathways plays a crucial role in this process. Several monogenic syndromes associated with autism, notably fragile X syndrome and tuberous sclerosis complex (TSC), involve proteins that function in these translational regulatory pathways.

One copy of 22q11.2, a segment of chromosome 22 that includes several genes, is missing in 1 of every 4,000 individuals. This non-inherited genetic abnormality results in some physical abnormalities, most of which can be repaired surgically early in life. But the most pernicious deficits associated with this microdeletion are cognitive, including severe learning disabilities and a high risk for mental illness, such as autism and schizophrenia. An improved understanding of the mechanisms that contribute to these psychiatric and cognitive symptoms is essential for providing better treatments.