KIRREL2 encodes an immunoglobulin superfamily cell adhesion molecule with five immunoglobulin domains, one transmembrane domain, and an intracellular domain 1. The protein is predominantly expressed in pancreatic beta cells, where it may regulate basal insulin secretion 1. In the kidney, KIRREL2 functions as part of the glomerular filtration barrier in podocytes, working alongside nephrin to maintain normal glomerular ultrafiltration through cell adhesion and signaling mechanisms 2. The protein also plays a critical role in nervous system development, particularly in olfactory sensory neuron axon coalescence, where KIRREL2 homodimerizes to help segregate axons into specific glomeruli 3. Clinically, KIRREL2 mutations are associated with protein-losing nephropathy in dogs and increased risk of steroid-resistant nephrotic syndrome in children 45. In Group 3 medulloblastomas, high KIRREL2 expression serves as an independent prognostic marker for poor survival outcomes, enabling better risk stratification of patients 6. Additionally, KIRREL2 has been identified as a potential biomarker associated with polycystic ovary syndrome risk through Mendelian randomization analysis 7.