A man with Fabry’s disease, who died at 52, suffered from lancinating limb pains between the age of 20 and 27, and from severe arthralgia between 20 and 40. The sural nerve showed a severe loss of fibers (1,614 myelinated fibers/mm²), chiefly affecting the small myelinated fibers. Inclusions of both homogeneous and lamellated appearance were present in the perineurial cells, fibroblasts and vessel walls. Teased fibers displayed moderate remyelination, regeneration and the presence of globular focal myelin thickening. The transient time course of painful manifestations in this case is stressed in view of a possible pathogenesis of pain in Fabry’s disease. It appears that small-fiber neuropathy is not directly related to the occurrence of pain symptoms, since the prevalent loss of small myelinated fibers was seen in the absence of actual pain. The small sensory neurons in the dorsal root ganglia, that are especially affected by lipid accumulation, probably give rise to abnormal discharges producing pain via the prevalence of the small-fiber versus the large-fiber input to the dorsal horn of the spinal cord (gate control theory). Thus pain fits may spontaneously abate, as in our case, if degeneration and loss of the small sensory neurons overstep a critical level.

A 65-year-old man with Tangier disease (analphalipoproteinemia) had had a progressive sensorimotor distal neuropathy with sensory ataxia for 1 year. Muscle biopsy demonstrated excess lipid vacuoles on histochemical and electron-microscopic techniques. Sural nerve biopsy showed a marked loss of large fibers and an increase in small myelinated fibers, with presence of remyelinating fibers and clusters of regeneration; a few aspects of active demyelination and some onion-like formations were also present. Lipid accumulation chiefly affected the Schwann cells of unmyelinated fibers and, to a lesser degree, of myelinated fibers, endoneurial fibroblast, and vasa nervorum. Teased fibers showed prevalent aspects of de-/remyelination and, often in association, marked myelin wrinkling suggesting axonal atrophy. This Tangier patient differs from known cases for the presence of a distal symmetrical sensorimotor polyneuropathy (not previously reported in Tangier disease) and because of the morphological findings of de-/remyelination coexisting with aspects of axonal atrophy and previous degeneration, and of lipid accumulation within striated muscle and vasa nervorum. This latter finding contrasts with the assumption that in Tangier disease vessel walls are not a site of lipid storage: probably the vasa nervorum are different, in this respect, from other vessels, because of the intense lipid metabolism of the nervous tissue. Thus we suggest that involvement of vasa nervorum in Tangier disease may be more important than previously suspected, possibly playing a role in the causation of neuropathy.

A case of progressive external ophthalmoplegia (PEO) in association with peripheral neuropathy and other neural and visceral manifestations is reported. Pathological studies of the sural nerve demonstrated loss of large myelinated fibers, segmental demyelination with remyelination, and excess of zebra bodies in the Schwann cells on electron microscopy. Peripheral neuropathy in the course of PEO is regarded as a further although rare aspect of a multisystem disease.

No abstract