Autism may involve different levels of RNA isoforms encoded by genes in the brain, which express many more proteins than previously thought.

As 2021 comes to a close, Spectrum recaps some of the biggest trends in autism science this year: studies of sex differences, noncoding regions of the genome and points of convergence, as well as efforts to improve screening and participatory research.

Developmental delay, intellectual disability and behavioral issues are common among people who have mutations in MYT1L, a gene with strong ties to autism.

Many genes linked to autism are switched on in the brain’s glia, cells that help neurons develop and synapses form.

Spontaneous genetic mutations contribute to autism in 30 to 39 percent of all people with the condition, and 52 to 67 percent of autistic children whose siblings do not also have the condition.

An advanced DNA-sequencing technique has identified gene-damaging mutations, some with ties to autism, in about 1 in 15 men.

Spontaneous mutations in parts of the genome that regulate gene EBF3 appear to contribute to autism risk.

Mosaic mutations, which affect only some of the body’s cells, play a small but meaningful role in autism. Though they are difficult to study, researchers are working to master their complexity.

Cross-species comparisons can help make sense of subtle genetic variants in people with autism and identify hundreds of new genes that may contribute to the condition.

The more scientists dig into DNA, the more intricate its contribution to autism seems to be. Here, we unravel the complex genetics of autism.