Environment

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.

Scientists have identified distinct blood signatures of cytokines — proteins that control communication between cells of the immune system — in individuals with fragile X syndrome and autism.

Young mouse models of fragile X syndrome show a significant lag in the development of synapses, the connections between neurons, according to a study published in Neuron. The findings suggest that a similar mistiming may be responsible for the sensory problems — such as hypersensitivity to touch and sound — sometimes seen in people with fragile X syndrome.

The ability to recognize faces and interpret facial expressions is programmed partly by genes and inherited separately from other traits, according to three independent studies published this year.

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.

Several genetic and animal studies in the past year have found intriguing ties between autism and DISC1, one of the oldest candidate genes for psychiatric disorders.

A class of medications widely used during pregnancy to treat asthma and prevent early labor increases the baby’s risk of autism and other psychiatric disorders, according to a controversial review in the American Journal of Obstetrics and Gynecology.