Fig. 1.
Loss of IENFs. Immunohistochemical studies (polyclonal anti-protein gene product 9.5 antibody) in sections of skin biopsy at distal leg in a father–son pair (A and B), both harboring L554P mutation in Nav1.8, and in healthy subject (C). Arrows indicate IENF; arrowheads indicate dermal nerve bundles. Patient 2 (A) showed complete depletion of IENFs and severe reduction in density of dermal nerve bundles, which appeared fragmented due to axonal degeneration. Patient 1 (B) showed almost complete loss of IENFs. Inset shows IENF (white arrow) branching after penetrating the epidermis, with large swelling (bent arrow) representing typical axonal predegeneration state. A and B are typical of SFN. For comparison, C shows diffuse innervation of epidermis and dermis in a healthy subject. (Scale bar, 50 μm.)