Involvement of peripheral nerve and muscle in Fabry's disease. Histologic, ultrastructural, and morphometric studies.

Light microscopic and ultrastructural studies of biopsy specimens from the sural nerve and the gastrocnemius muscle in a patient with Fabry's disease showed accumulation of lipids in endothelial and perithelial cells of the vessel walls. In addition, the peripheral nerve exhibited deposition of lipids in the perineurial cells, occasionally in unmyelinated and myelinated axons, and infrequently in Schwann cell cytoplasm. In the muscle biopsy specimen, stored lipid was found in the sarcoplasm. Quantitative histologic studies showed loss of large unmyelinated and thin myelinated nerve fibers. Excruciating pain and loss of sweating, characteristic of this disorder, may result from loss of these fiber categories. The peripheral neuropathy is probably secondary to perikaryal deposition of lipid as described previously in the literature.