The percentages of TuJ-1- and GFAP-expressing cells were not different between patients and controls (percent over DAPI; P = 0.24 and 0.26, respectively, Fig. 2D, and Supplementary Material, Fig. 2A), indicating that patient and control hiPSCs were able to form NPC lines giving rise to neurons and glia with variation between lines but no significant difference between SPG4 and controls. This evidence concerns the gene SPAST and nasopharyngeal carcinoma.