Studies Indicate How Mosaic Mutations Contribute to Autism Risk January 13, 2021 Two studies published in Nature Neuroscience implicate mosaic mutations arising during embryonic development as a cause of autism spectrum disorder (ASD). The investigations, led by researchers at Boston Children’s Hospital, Brigham and Women’s Hospital (BWH), and Harvard Medical School (HMS), point to new areas for exploring the genetics of ASD and could eventually inform diagnostic testing. The two reported studies were part of the Brain Somatic Mosaicism Network, funded by the National Institute of Mental Health. One study (“The landscape of somatic mutation in cerebral cortex of autistic and neurotypical individuals revealed by ultra-deep whole-genome sequencing”) exploited deep, ultra-high-resolution whole-genome sequencing to quantify and characterize mosaic mutations in the frontal cortex of people with and without ASD. The research was led by Rachel Rodin, MD, PhD, and Christopher Walsh, MD, PhD, of Boston Children’s, together with Yanmei Dou, PhD, and Peter Park, PhD, of HMS. The other study (“Large mosaic copy number variations confer autism risk”) published in the same issue of