We also extend on our earlier findings of altered balance of these CTIP2+BRN1+ neurons in brains with Ddx3x haploinsufficiency (Fig. 3), which in humans is associated with a complex NDD manifesting with ID and ASD (Lennox et al., 2020; Levy et al., 2023; Snijders Blok et al., 2015). This evidence concerns the gene DDX3X and Neurodevelopmental delay.