DOCK9

This protein functions as a guanine nucleotide-exchange factor that activates CDC42 and induces filopodia formation, playing a role in cellular signaling and cytoskeletal organization. Mutations cause intellectual disability and developmental delay with variable additional features including seizures, behavioral abnormalities, and dysmorphic features, following an autosomal dominant inheritance pattern. The gene is highly constrained against loss-of-function variants, indicating intolerance to protein-disrupting mutations.