Nociception, intracellular calcium signalling, and microglia activation are all potentially relevant for CH pathophysiology; the first line preventative CH treatment, being a calcium channel blocker, and the top GWAS loci identified for CH, MERTK, being primarily expressed in microglia and other glial cells [13, 24]. The gene discussed is MERTK; the disease is cyclic hematopoiesis.