The Rett syndrome gene MeCP2 may subtly regulate the expression of genes across the genome by altering DNA structure.

An autism-linked protein helps wire neurons together, according to two studies published in late September.

Researchers have created detailed three-dimensional reconstructions of the numerous complex branches of dendrites, the signal-receiving ends of neurons.

Loss of MeCP2, the Rett syndrome gene, in neurons that release the chemical messenger dopamine may lead to the motor deficits associated with the syndrome.

The first study to sequence more than 100 genes on the X chromosome in people with autism or schizophrenia has turned up some promising leads.

Deletions or duplications of the UBE3A gene lead to both Angelman syndrome and some cases of autism, respectively. Studying the effects of altered gene dosage in this region will provide insights into brain defects and suggest targets for therapies for both disorders, says expert Benjamin Philpot.

Disrupted-in-schizophrenia 1, or DISC1— a protein associated with both autism and schizophrenia — is involved in the transport of mitochondria, the power-houses of the cell, to their correct locations in neurons, according to a study published in February in Molecular Psychiatry.

A partial mutation that leads to a milder form of fragile X syndrome causes deficits in learning and memory in mice, and alters the connections between their neurons, according to a study published in January in Neurobiology of Disease.

Men with fragile X syndrome have larger brains overall than controls do, but less matter in regions involved in language and social interaction.

Using tricks of genetic engineering, researchers in Taiwan have created the first comprehensive map of the myriad neuronal connections in the fruit fly brain. The findings appeared 11 January in Current Biology.