FGFR3 and neuropathy, small fiber: We performed anti-FGFR3 ELISA on 42 serum samples of patients with sensory neuronopathy (n = 18), small fiber neuropathy (n = 18), and healthy controls (n = 6) in two independent centers in France (center 1) and Germany (center 2) using identical protocols, with double immunofluorescence staining on rat dorsal root ganglion (DRG) sections as a confirmational test.