A whopping 95 percent of children with autism have at least three other psychiatric disorders, and 74 percent have five or more, according to a study in the Journal of Autism and Developmental Disorders.

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.

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.

The proposed connection between premature birth and autism may be more complicated than it seems, according to a new report. Early birth may not cause classically defined autism but, rather, may predispose children to autism-like symptoms that are part of a larger syndrome, the researchers say.

Researchers have found a higher density of several types of interneurons — nerve cells that connect sensory and motor neurons in the brain— in postmortem brain tissue from individuals with autism, compared with healthy controls. The findings appear in the February issue of Acta Neurologica Scandinavica.

Genetic variations that tweak the brain’s release of oxytocin — a hormone involved in social bonding and establishing trust — may increase the risk of developing autism or traits of the disorder, according to three new studies published in the past few months.

A new mutation in the neuroligin-4 (NLGN4) gene, one of the few genes convincingly tied to autism, has been found in two brothers with autism, further implicating the gene in the disorder, scientists reported in the Journal of Neuroscience.

A newer version of the psychiatric manual may expand the definition of autism, folding in Asperger syndrome and pervasive developmental disorder not otherwise specified.

Serotonin is most commonly talked about in association with depression and anxiety. But for nearly 50 years, hyperserotonemia ― an elevated level of blood serotonin ― has been noted in roughly a third of autism cases.

Two research groups have achieved an elusive goal: producing mouse models that show distinct social and behavioral abnormalities reminiscent of autism.