Scientists used the gene-editing tool CRISPR to create two marmosets lacking MECP2, the gene mutated in Rett syndrome.

Mice lacking one copy of a gene linked to autism are small and show striking changes in the number and quality of their cries.

The largest-ever set of sequences from people with developmental delay has revealed 43 new genetic diagnoses.

Clusters of brain cells — so-called ‘mini-brains’ grown in the lab — may help researchers understand how large stretches of duplicated or deleted DNA affect the brain.

Genes linked to autism in sequencing studies tend be located in long stretches of DNA that are duplicated or missing in some people with developmental conditions.

The largest autism sequencing study to date implicates 99 genes in the condition — but nearly half have a tighter link to intellectual disability or developmental delay.

It is not a matter of whether there will be clinical trials of genetic therapy for Angelman syndrome, but when.

Autism is more heritable than anorexia, alcohol dependence, depression and obsessive-compulsive disorder, according to an analysis of data from nearly 4.5 million people.

A new technique reveals the active genes and the regions that regulate them in thousands of single cells at once.

A remote Colombian town is home to the world’s largest cluster of people with fragile X syndrome. Scientists are learning from them — and trying to help.