CELSR1 (cadherin EGF LAG seven-pass G-type receptor 1) is an atypical adhesion G protein-coupled receptor that plays critical roles in epithelial planar cell polarity and nervous system development. The protein contains an extracellular domain with cadherin repeats, epidermal growth factor-like repeats, and laminin A G-type repeats coupled to a seven-transmembrane domain 1. CELSR1 functions as a key regulator of planar cell polarity (PCP) signaling, controlling morphogenetic movements during gastrulation and neural tube closure through convergent extension movements and oriented cell behaviors 2. The receptor engages G proteins via distinct activation mechanisms, with CELSR1 being cleavage-deficient yet retaining GαS coupling activity independent of tethered agonist mechanisms 3. Recent evidence identifies CELSR1 as a receptor for the tumor suppressor protein Reprimo, linking it to the Hippo-YAP/TAZ-p73 apoptotic pathway 4. CELSR1 expression is developmentally regulated and continues into adult life, with brain expression localized to ependymal cells, choroid plexus, and area postrema 1. Clinically, CELSR1 variants are associated with congenital lymphatic anomalies and fetal edema, with variants of uncertain significance identified in cases of fetal hydrops 5. The gene also serves as a marker for pulp stem cells in dental tissues 6.