KATNAL1 encodes a microtubule-severing enzyme that regulates cellular microtubule dynamics through ATP-dependent cleavage. In neurons, KATNAL1 is the dominant katanin isoform, showing higher severing activity and greater cellular stability than its paralog KATNA1, with selective expression in brain and testis tissues 1. KATNAL1 plays critical roles in neuronal process elongation and development; loss-of-function mutations in mice cause behavioral deficits including circadian rhythm and learning/memory impairment, along with neuronal migration abnormalities and defective motile cilia in ependymal cells 2. In humans, heterozygous microdeletions encompassing KATNAL1 are associated with intellectual disability, microcephaly, and atopic dermatitis, suggesting the gene contributes to CNS development 3. However, direct KATNAL1 mutations show no significant association with azoospermia in humans despite murine studies indicating male fertility involvement 4. Beyond protein-coding functions, the circular RNA derived from KATNAL1 (circ_KATNAL1) functions in immune regulation and cancer pathways, modulating inflammation through miR-153-3p/TLR4 signaling in epithelial cells 5 and suppressing prostate cancer growth via miR-145-3p/WISP1 regulation 6. These findings establish KATNAL1 as essential for neuronal development and suggest pleiotropic roles in reproductive and inflammatory processes.