Among the GTEx tissues with the most TWAS and SMR signals was the dorsolateral prefrontal cortex (dlPFC). To gain insight into cell type resolution, we conducted MAGMA for cell-type-specific markers of dlPFC and cell-type-specific SMR. MAGMA showed a significant enrichment of dlPFC inhibitory and excitatory neurons, but also of oligodendrocytes and oligodendrocyte precursor cells (Supplementary Table 18), while the SMR analyses identified cell-type-specific signals for 8 genes (KANSL1, ARL17B, LINC02210-CRHR1, LRRC37A2, ENSG00000262633, MAPT, ENSG00000273919, PLEKHM1) over 3 loci (6 out of 8 from 17q21.31) and all cell types (P < 0.05/1,885 unique genes tested) whose expression levels were potentially causally associated with PTSD (Supplementary Table 19). The top gene, KANSL1, was significant in all cell types.
