PCDHA1 (protocadherin alpha 1) is a calcium-dependent cell-adhesion molecule involved in establishing and maintaining specific neuronal connections in the brain 1. As part of the clustered protocadherin-alpha gene family, PCDHA1 undergoes dual regulatory expression patterns in cerebellar Purkinje cells, with individual neurons randomly expressing different combinations of Pcdha1-12 while constitutively expressing 3' genes 1. The protein plays critical roles in axonal projection, learning, and memory functions 1. PCDHA1 is implicated in neurodevelopmental disorders: de novo disruptive variants were identified as novel candidates in autism spectrum disorder and intellectual disability cases 2, and rare pathological variants were found in polymicrogyria, a cortical malformation disorder 3. Beyond neurodevelopment, PCDHA1 mutations appear relevant to cancer biology, including gastric cancer where clonal mutations were identified in Latino patients 4, and breast cancer where specific PCDHA1 mutations correlated with pathological response to neoadjuvant chemotherapy 5. DNA methylation levels at PCDHA1 loci showed correlation with gene expression in prostate cancer tissues 6. These findings suggest PCDHA1's role extends from neuronal cell adhesion and neural development to potential oncological significance, warranting further investigation of its mechanisms across diverse biological contexts.