YY1AP1 (YY1 associated protein 1) is a chr1 regulatory protein that functions as a co-factor enhancing transcriptional activation by the YY1 transcription factor. YY1AP1 associates with the INO80 chr1 remodeling complex, which mediates transcriptional regulation, DNA repair, and DNA replication 1. The protein plays an important role in cell cycle regulation 21. Structurally, YY1AP1 localizes to nuclear compartments including the nucleoplasm and nucleolus, consistent with its transcriptional regulatory functions. While the provided abstracts focus primarily on YAP/TAZ signaling rather than YY1AP1 specifically, recent evidence suggests YY1AP1 may be relevant to neurodevelopmental disease pathways. YY1AP1 is mentioned within the context of chr1 genes—those encoding epigenetic regulatory proteins—that regulate autophagy-related genes, which control autophagic activity crucial for neuronal health and development 3. Aberrant autophagic regulation potentially underlies nervous system impairments in neurodevelopmental disorders with disturbed epigenetic regulation. Clinically, YY1AP1 mutations are associated with Grange syndrome. The molecular mechanisms linking YY1AP1 dysfunction to disease pathogenesis require further investigation, though its role in chr1 remodeling and transcriptional regulation suggests effects on gene expression programs critical for normal development and cellular homeostasis.