Fig. 4.

Representative histopathology of the peroneal nerve from male Leonberger dog with polyneuropathy and heterozygous GJA9 genotype. Resin embedded peroneal nerve sections collected post-mortem from a 5 year old male intact Leonberger dog with clinical signs of polyneuropathy. a Toluidine blue-acid fuchsin stain showing loss of predominantly large myelinated fibers and qualitatively increased populations of small calibre nerve fibers. b Paraphenelenediamine stain for myelin showing thin but intact myelin sheaths in many small nerve fibers. For comparison, images (c, toluidine blue-acid fuchsin stain) and (d, paraphenelenediamine stain) are from the peroneal nerve of a 6 year old female neutered Leonberger dog that was negative for both the ARHGEF10 and GJA9 variants and without clinical signs of polyneuropathy