a, Heatmap showing log2FPKM values of sub-type marker genes in hiPSC-neurons across genotypes. b, Cell type composition scores obtained using Cibersort4 in hiPSC-neurons (9 controls, 4 donors; 9 cases, 4 donors), by diagnosis. c, Images of GABA immunostaining overlaid with MAP2. d, Mean percent of GABA+ cells from control (8 images, 2 coverslips), 5’-NRXN1+/- (8 images, 2 coverslips) and 3’-NRXN1+/- (11 images, 3 coverslips). Error bars are s.e. e, Representative images of SYN1 immunostaining alone and overlaid with MAP2 immunostaining and DAPI. f, Mean intensity of SYN1+ puncta normalized to MAP2 intensity (3 images per coverslip, 8 coverslips per donor, 2 donors per genotype). Error bars are s.e.