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Four Navajo children had a mutilating neuropathy with severe motor involvement. The disorder appears to be recessively inherited and is present from the earliest observable age. Manifestations include severe anesthesia, corneal ulceration, painless fractures, acral mutilation, and weakness. Mental function is normal. Sural nerves are practically devoid of myelinated fibers that show no evidence of regeneration. Unmyelinated axons show degenerative and regenerative morphologic and histometric features. Onion bulb formation is absent. We believe this neuropathy is a distinct clinical entity.

Three family members had the unusual combination of severe peripheral neuropathy, atypical hereditary ataxia, spongy degeneration of cerbral hemispheres, and cerebellar and brainstem foci of necrotizing encephalopathy, proved pathologically in one autopsied case. A sural nerve from a patient, devoid of myelinated fibers, was transplanted into thymectomized, lethally irradiated, and bone marrow reconstituted adult mice. A normal number of myelinated fibers was present in the grafts eleven weeks later. Eighteen weeks after grafting, mice were reconstituted with syngeneic thymus to return immunocompetence. Schwann cells in the graft were rejected and axons became totally denuded of myelin after thymus reconstitution. The peripheral neuropathy is thus due to axonal disease since human Schwann cells were capable of normally myelinating regenerating mouse axons. A puzzling feature after rejection was the absence of myelin debris containing macrophages in the grafts. It is suggested that part of the rejection process in this model is mediated by antibody rather than by cellular mechanisms.