A significant reduction in full-length TrkB (TrkB-FL)/truncated TrkB (TrkB-T1 + TrkB-Shc) isoform ratio and increase in the ratio of truncated TrkB isoforms/TrkB-FL (**p = 0.002, Figure 5A; **p = 0.009, Figure 5B; 2-tailed t tests) were observed in the fusiform gyrus of individuals with idiopathic autism versus controls. This evidence concerns the gene NTRK2 and autism.