To find the pathogenic mutations in complex disorders such as autism, researchers may need to conduct sophisticated analyses of the genetic functions that are disrupted, says geneticist Aravinda Chakravarti.

We can’t get back the tissue lost in the Harvard freezer malfunction, but we can try to create something positive from this tragic event, says Alison Singer.

Studies of autism prevalence should screen a representative sample of all individuals in the population, even those with no indications of the disorder, says epidemiologist Young-Shin Kim.

Social impairments in autism are likely a consequence of deficits in social motivation that start early in life and have profound developmental consequences, says psychologist Robert Schultz.

Childhood disintegrative disorder represents a distinct entity within the autism spectrum and it should remain a separate diagnostic category, says Kevin Pelphrey.

Accurately measuring the severity of autism remains a challenge for the field. The answer may lie in using more than one approach that varies depending on whether it is being applied in a clinical or research context, says Raphael Bernier.

Dysregulation of the intracellular signaling pathway RAS, a risk factor for idiopathic autism, may provide a unifying theory of the disorder. Although this is not an altogether new hypothesis, several new findings have strengthened the evidence for it considerably.

The characteristics, interactions and roles of autism-associated genes in the fruit flies’ brain will help guide how we think about the same genes in humans, says Ralph Greenspan.

Maternal antibodies that attack fetal brain proteins could underlie some cases of autism, says immunologist Betty Diamond.

Autism and attention deficit hyperactivity disorder show genetic and neurobiological overlap, which may provide clues to the origin of both disorders, says Joel Nigg.