CEP78 (centrosomal protein 78) is a centriole wall protein that localizes to mature centrioles and serves as a critical regulator of centriole and cilia biogenesis 12. CEP78 functions downstream of CEP350 to control primary cilia formation by negatively regulating CP110 levels through its interaction with the EDD1-DYRK2-DDB1VPRBP E3 ubiquitin ligase complex 34. The protein prevents ubiquitination and degradation of centrosomal proteins including CCP110 and tektin proteins (TEKT1-5) 43. CEP78 regulates centriole elongation and controls cilium length by interacting with intraflagellar transport proteins IFT20 and TTC21A 5. Pathogenic CEP78 mutations cause cone-rod dystrophy with hearing loss (CRDHH), characterized by retinal photoreceptor dysfunction and sensorineural hearing impairment 67. CEP78 deficiency also causes male infertility with multiple morphological abnormalities of sperm flagella (MMAF), including disrupted 9+2 microtubule structures and abnormal flagellar morphology 85. Loss of CEP78 leads to abnormal centriole elongation, cilia shortening, disrupted photoreceptor outer segment organization, and impaired sperm motility 5. These multi-system manifestations underscore CEP78's essential role in maintaining ciliary and centrosomal integrity across diverse tissues.