IL1RAPL2 and bipolar disorder: By integrating scRNA-seq with the differential expression of the GWAS genes of major psychiatric disorders in different excitatory neuron subtypes of p21 and p60 mPFCs, we identified an mPFC L5 IT neuron subtype, marked by the expression of the Il1rapl2 gene, characterized by differential expression of a large number of genes associated with social deficit disorders such as autism and bipolar disorder (Fig. 1B, Exc_8).