CRISPR knockout screens reveal genes and pathways essential for neuronal differentiation and implicate PEDS1 in neurodevelopment.

Neurodevelopmental disorders (NDDs) arise from disruptions in brain development, yet the underlying pathways remain incompletely understood. Here we demonstrate that genome-wide CRISPR knockout screens in mouse embryonic stem cells differentiating into neural lineages identify hundreds of essential genes, only a minority of which are currently implicated in NDDs. Dominant NDD genes were enriched for transcriptional regulators, whereas recessive NDD genes were predominantly involved in metabolic processes. Mouse models for eight genes (Eml1, Dusp26, Dynlrb2, Mta3, Peds1, Sgms1, Slitrk4 and Vamp3) revealed marked neuroanatomical abnormalities, including microcephaly in half of the cases. Focusing on PEDS1, a key enzyme in plasmalogen biosynthesis, we identified a bi-allelic variant in individuals with microcephaly, global developmental delay and congenital cataracts. In mice, Peds1 deficiency led to accelerated cell-cycle exit and impaired neuronal differentiation and migration. These pathways required for neural differentiation provide a genetic framework for discovering additional NDD genes.