Reduced dendritic arborization has been observed in postmortem SCZD brains11 and in animal models12. SCZD hiPSC neurons show a decrease in the number of neurites (Fig. 3A; SI Fig. 9A,B). Synaptic genes are associated with SCZD13 (SI Fig. 9D) and impaired synaptic maturation occurs in a number of mouse models12. hiPSC neurons express dense puncta of synaptic markers that co-stain for both pre- and post-synaptic markers (SI Fig. 8A,B). While we observed decreased PSD95 protein expression relative to MAP2AB in SCZD hiPSC neurons (Fig. 3B; SI Fig. 9H), the levels of SYN, VGLUT1, GLUR1, VGAT and GEPH were unaffected (SI Fig. 9E–J). Decreased PSD95 synaptic density in SCZD hiPSC neurons failed to reach statistical significance (Fig. 3C; SI Fig. 9C).
