It is reduced in expression in skin biopsies from patients with diabetic neuropathy72,73 but increased in expression in early-stage peripheral neuropathies.56 GAP43 was first demonstrated in the cornea by Martin and Bazan45 and is one of several RAGs genes whose mRNA expression increases 14 days after lamellar flap surgery.46 Here, EFNA5 is linked to peripheral neuropathy.