Neuroscientists have discovered a population of cells in the smell-perception area of the rat brain that express the hormone vasopressin. The study, published in Nature, begins to unpack the complicated molecular interactions of the hormone in the brain, which could lead to new autism treatments.

Researchers are tinkering with mouse models to investigate the function of a protein that helps wire neurons together and that has repeatedly been linked to autism. Three such reports of the protein, neuroligin-1, have appeared this year.

Two independent teams have identified the genetic culprits of three rare, inherited diseases by sequencing the genomes of several members of the same family. As the cost of whole-genome sequencing plummets, this family-based approach will reveal candidate genes not just for rare diseases but for common, complex disorders such as autism, experts say.

Two independent teams have discovered key molecular steps in the way a single gene disrupts the connections between neurons in individuals with Angelman syndrome. Because the gene, UBE3A, has also been linked to autism, the findings could help scientists understand and treat a range of neurodevelopmental disorders.

Attention deficit hyperactivity disorder (ADHD) and autism may have more in common than childhood onset and a few similar symptoms. New research suggests the conditions share genetic roots.

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.

Toddlers with autism pay less attention to faces than do healthy controls, but both groups give equal attention to objects, according to a study published in the Archives of General Psychiatry. The findings challenge the idea that individuals with autism have a generalized problem with attention, suggesting instead that they struggle with attending specifically to social stimuli, researchers say.

Random changes in gene expression can cause genetically identical embryos to develop different traits, according to a study of worms published in Nature. The findings suggest that haphazard movements of molecules could partly explain why autism-associated mutations don’t always cause the same symptoms.

The protein that is mutated in Rett syndrome controls the expression of other genes by changing the way DNA packs into a cell, rather than turning genes on or off, according to a study published in Molecular Cell.

At 6 months of age, babies who will later develop autism begin to lose some of their social skills and continue to regress until age 3, according to a study published in the Journal of the American Academy of Child & Adolescent Psychiatry.