Genetic variants in two autism-associated genes have been linked to repetitive behavior and hyperactivity, two common symptoms of the disorder, according to two studies published in the past few months.

Small fragments of RNA, called microRNAs, can fine-tune the levels of proteins at the junctions between neurons in response to cell signals, according to a study published 10 June in Molecular Cell.

Several targeted trials on drugs that treat fragile X syndrome are under way. But accurate endpoints to measure the drugs’ effectiveness are crucial, argues developmental and behavioral pediatrician Randi Hagerman.

A new study provides the first functional link between the schizophrenia risk gene DISC1 and two candidate genes for autism. DISC1 significantly alters expression of NRXN1 and NRXN2 at key phases of development, according to a brief report in the June issue of Molecular Psychiatry.

Identical twins can be genetically different, which could explain why they do not always share disorders such as schizophrenia or autism, according to a study published in March in PLoS One.

Lithium ameliorates some of the cognitive and behavioral deficits associated with fragile X syndrome by blocking GSK-3, an enzyme that plays a key role in development, researchers said Wednesday at the Society for Neuroscience annual meeting in San Diego.

For a few hundred dollars and a bit of your spit, you can have parts of your DNA analyzed. If you’re more ambitious, $20,000 — and a lot less than that a year from now — will buy you the sequence of your entire genome. But the real question is should you, and others like you, find out what secrets your genome holds?

One of the largest genome-wide association studies for autism spectrum disorders, reported last week in Human Molecular Genetics, allows only one definitive conclusion: it isn’t large enough.

Babies born to rhesus monkeys infected with the flu virus during pregnancy have significantly smaller brains than normal, and other brain abnormalities seen in schizophrenia, researchers have found. The study, published last month in Biological Psychiatry, provides the first evidence in non-human primates linking flu infection to a higher risk of schizophrenia.

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.