CEP104 is a centrosomal and ciliary tip protein essential for ciliogenesis and ciliary structural integrity 1. It contains a tubulin-binding TOG (tumor overexpressed gene) domain and a C2HC zinc finger array that enable interaction with tubulin and the kinase Nek1 2. CEP104 functions as part of a ciliary tip protein module including CSPP1, TOGARAM1, ARMC9, and CCDC66 3. This complex regulates axonemal microtubule dynamics by inhibiting both microtubule growth and shortening, with TOGARAM1 counteracting growth inhibition to produce slow, processive microtubule elongation characteristic of axonemes 4. The CEP104-CSPP1 interaction specifically regulates axoneme length and is required for Hedgehog signaling competence in primary cilia 1. Pathogenic CEP104 variants cause two distinct neurodevelopmental phenotypes. Most commonly, mutations cause Joubert syndrome 25 (JBTS25), a ciliopathy characterized by hindbrain malformation and the pathognomonic molar tooth sign 5. However, CEP104 dysfunction also causes intellectual developmental disorder with broader clinical variability—some patients present with intellectual disability and hypotonia without JBTS-associated brain anomalies 6. CEP104 mutations result in shortened cilia with decreased axonemal post-translational modifications 3, disrupting both developmental signaling and sensory ciliary functions critical for normal neurodevelopment 7.