RAC3 and neurodevelopmental disorder: While a variety of genes encoding molecules involved in RAC signaling pathways have been implicated in neurodevelopmental disorders (NDDs) (12, 13), recent studies have revealed that de novo deleterious variants in the human RAC1 (MIM ∗ 602048) and RAC3 (MIM ∗ 602050) genes are directly implicated as the cause of neurodevelopmental phenotypes (14, 15, 16, 17, 18, 19, 20, 21, 22).