MPHOSPH9 (M-phase phosphoprotein 9) is a cell cycle-associated protein that functions as a negative regulator of ciliogenesis and has emerged as a significant factor in multiple disease contexts. The protein negatively regulates cilia formation by recruiting the CP110-CEP97 complex to the distal end of the mother centriole in ciliary cells 1. During cilia formation initiation, MPHOSPH9 undergoes TTBK2-mediated phosphorylation and subsequent degradation via the ubiquitin-proteasome system, removing itself and the CP110-CEP97 complex to promote ciliogenesis 1. MPHOSPH9 has demonstrated clinical relevance across multiple diseases. It serves as a novel susceptibility locus for multiple sclerosis, where the risk allele correlates with diminished CDK2AP1 expression, potentially affecting autoreactive cell proliferation 2. In gastric cancer, MPHOSPH9 upregulation associates with poor prognosis and activates mTOR signaling pathways 3. The gene also shows associations with type 2 diabetes, with regulatory variants identified in pancreatic islet cells 4 and evidence for evolutionary selection effects on insulin action in African populations 5. Additionally, MPHOSPH9 has been identified as a shared genetic risk factor between gastroesophageal reflux disease and asthma 6 and incorporated into prognostic models for low-grade glioma 7.