LY6H (lymphocyte antigen 6 family member H) is a GPI-anchored cell surface glycoprotein that functions as a modulator of nicotinic acetylcholine receptor (nAChR) activity in the nervous system 1. The protein specifically inhibits α7-containing nAChRs by competing with NACHO for access to α7 subunits, thereby regulating receptor assembly and maintaining activity within physiological ranges 2. LY6H is highly expressed in specific brain subdivisions and plays a crucial role in neuronal function and viability by preventing excessive Ca2+ influx through α7 nAChRs 12. In Alzheimer's disease, amyloid β-driven reduction in LY6H disrupts this regulatory balance, leading to increased phosphorylated tau and α7-mediated neurotoxicity 2. LY6H also serves as a specific cell surface marker for pancreatic delta cells and can be used to enrich these cells from human islet preparations 3. Recent studies have identified LY6H as a potential biomarker, with reduced expression associated with glioma-related epilepsy 4 and novel genetic associations discovered in Alzheimer's disease through machine learning approaches 5. The protein's expression correlates with inflammatory responses in colorectal tissues, suggesting broader roles in disease pathogenesis 6.