TTC27 is a tetratricopeptide repeat (TPR) domain-containing protein that functions in cell fate determination and stem cell regulation. In C. elegans, the TTC27 homolog TRD-1 is essential for proper cell fate choice in both the germline and developing epidermis, acting downstream of tra-2 but upstream of fem-3 in sex determination pathways 1. The protein exhibits roles in regulating the mitosis-to-meiosis transition and maintaining appropriate seam cell identity, with loss-of-function resulting in inappropriate cellular differentiation 1. Comparative transcriptomic analysis across planarians, mice, and humans identified TTC27 among conserved stem cell regulators critical for tissue homeostasis, regeneration, and stem cell maintenance 2. In human neurobiology, TTC27 has been associated with white matter hyperintensities (WMH) through genome-wide association studies, with SNP variants showing significant associations in multiple populations 3. These findings suggest TTC27 plays conserved roles in developmental cell fate determination and stem cell biology, with potential relevance to neurological phenotypes in Alzheimer's disease-related brain changes. However, the precise molecular mechanisms by which TTC27 executes these functions remain to be fully elucidated.