One in 54 children in the United States is diagnosed with autism spectrum disorder. De novo germline and somatic mutations cannot account for all cases of autism spectrum disorder, suggesting that epigenetic alterations triggered by environmental exposures may be responsible for a subset of autism spectrum disorder cases. Human and animal studies have shown that exposure of the developing brain to general anesthetic agents can trigger neurodegeneration and neurobehavioral abnormalities, but the effects of general anesthetics on the germline have not been explored in detail. We exposed pregnant mice to sevoflurane during the time of embryonic development when the germ cells undergo epigenetic reprogramming and found that more than 38% of the directly exposed F1 animals exhibit impairments in anxiety and social interactions. Strikingly, 44–47% of the F2 and F3 animals, which were not directly exposed to sevoflurane, show the same behavioral problems. We performed ATAC-seq and identified more than 1200 differentially accessible sites in the sperm of F1 animals, 69 of which are also present in the sperm of F2 animals. These sites are located in regulatory regions of genes strongly associated with autism spectrum disorder, including Arid1b, Ntrk2, and Stmn2. These findings suggest that epimutations caused by exposing germ cells to sevoflurane can lead to autism spectrum disorder in the offspring, and this effect can be transmitted through the male germline inter- and transgenerationally.

Summary sentence

Pregnant mouse F0 females exposed to sevoflurane give rise to F1 males with sociability and anxiety defects. These behaviors are transmitted to F2 and F3 males. Their sperm show changes in transcription factor occupancy in genes implicated in autism.

Graphical Abstract