In the peripheral nervous system (PNS), recent evidence highlights a PCSK9–CD36 axis in Schwann cells; genetic Pcsk9 loss elevates CD36, increases fatty-acid influx, promotes lipid droplet expansion and acylcarnitine accumulation, and triggers mitochondrial stress that manifests as hypomyelination, C-fiber pathology, and selective small-fiber neuropathy. The gene discussed is PCSK9; the disease is neuropathy, small fiber.