PCDH12 (protocadherin 12) is a non-clustered protocadherin family member that functions as a calcium-dependent cell adhesion molecule with critical roles in neural development and endothelial function 1. The protein belongs to the δ2 subgroup of non-clustered protocadherins and is predominantly expressed in the nervous system with spatiotemporally diverse expression patterns 1. PCDH12 mediates homophilic cell-cell adhesion and promotes cellular aggregation at intercellular junctions, playing essential roles in neural circuit formation and maintenance 1. Unlike classical cadherins, PCDH12 cannot bind to catenins and shows weak cytoskeletal association, suggesting distinct signaling mechanisms 1. Loss-of-function mutations in PCDH12 cause diencephalic-mesencephalic junction dysplasia syndrome 1 (DMJD), characterized by progressive microcephaly, brainstem malformations, developmental delay, epilepsy, and brain calcifications 23. Patient-derived cells lacking PCDH12 expression show impaired neurite outgrowth, reflecting the protein's crucial role in neural development 2. The clinical phenotype includes punctate brain calcifications in subcortical and perithalamic regions, distinguishing it from other brain calcification disorders 4. PCDH12 has also been implicated in various neuropsychiatric conditions and appears to have broader roles in endothelial function and immune-related processes 56.