POLR3B mutations resulting in Pol III complex assembly defects are known to be causal in POLR3-HLD.17 Therefore, we elected to study the Δ10 mutation in vivo in the context of oligodendrocyte precursor cell (OPC) development using an inducible/conditional Pdgfrα-CreERT system. This evidence concerns the gene PDGFRA and leukodystrophy.