Abstract
Peripheral nerve involvement was reported in a case of Sjögren-Larsson syndrome. The patient was a 10 year-old boy with congenital ichthyosis, spastic paraplegia, and mental retardation. The motor nerve conduction velocity of his right ulnar nerve was reduced to 19.3m/sec, and CSF protein was increased to 195mg/dl. The sural nerve biopsy was performed, and the specimen was fixed in 1% osmic acid, and embedded in Epon.
Light microscopically, presence of myelinated fibers measuring 8 ki or less in diameter, “onion -bulb” formation with proliferation of Schwann cells and endoneural fibrosis were recognized. Electron microscopically, irregularity in size and shape of unmyelinated fibers and crenation of the axon in myelinated fibers were noted. Prolifera tion of the myelin sheath, its separation from the axon cylinder, and its circumferential cleavage were also noted. Collagen fibrils proliferated markedly around the nerve fibers.
It was not clear whether Sjogren-Larsson syndrome usually had such peripheral nerve in volvement, or this case incidentally carried it. Although this case was initially regarded as the transitional type of Refsum's disease, the serun level of phytanic acid was normal contrary to its higher value in that disease. Morphological findings of the peripheral nerve in this case were suggestive of its congenital hypoplasia rather than a degenerative process. It is conceivable that Sjogren-Larsson syndrome has extensive disorders of the ectodermal tissues including the peripheral nerve as well as the skin or the central nervous system.
