Researchers used advanced long-read RNA sequencing on sorted human brain cell types from the prefrontal cortex, cataloging over 220,000 full-length RNA isoforms — more than half previously unknown. Contrary to expectations, glial cells (such as oligodendrocytes and microglia) showed greater isoform diversity than neurons. Importantly, disease-causing genetic variants were found to be enriched at newly discovered splice sites within genes including POGZ, suggesting that much of the pathogenic variation in White-Sutton syndrome and related conditions may be missed by standard gene annotation approaches.