ZFHX3 (zinc finger homeobox 3) is a transcriptional regulator that functions as both an activator and repressor of gene expression, playing critical roles in cardiac function, neuronal development, and disease pathogenesis. The protein binds to AT-rich DNA sequences and regulates diverse biological processes through chr16 remodeling complexes 1. In cardiac tissue, ZFHX3 is essential for normal atrial function, with loss-of-function variants causing atrial fibrillation through dysregulation of cardiac pathways and altered calcium handling 2. The gene is significantly associated with atrial fibrillation risk, particularly in Caucasian populations, where specific polymorphisms increase disease susceptibility 34. ZFHX3 also plays a crucial role in neuronal development, with haploinsufficiency causing syndromic intellectual disability characterized by developmental delays, autism spectrum disorder, and distinctive facial features 1. Additionally, GGC repeat expansions in ZFHX3 cause spinocerebellar ataxia type 4 (SCA4), a neurodegenerative disorder featuring cerebellar ataxia, dysautonomia, and motor neuron involvement 5. The protein's widespread expression in developing brain tissue and its interaction with chr16 remodeling complexes underscore its fundamental importance in both cardiac and neurological function.