Quantitative histological study of the sural nerve in a child with acid maltase deficiency (glycogenosis type II)

A boy diagnosed as having glycogenosis type II at three years of age, underwent a sural nerve biopsy at the age of seven years. The distribution of the diameters of myelinated nerve fibers did not clearly demonstrate a bimodal pattern. However, larger fibers of 8 microns or more in diameter were more abundant. This finding correlated with the motor conduction velocity which was within normal limits for his age. A striking feature was the accumulation of glycogen particles in Schwann cells of both myelinated and unmyelinated nerve fibers. The accumulation of glycogen particles was more prominent in Schwann cells of myelinated nerve fibers than in those of unmyelinated ones. The reason for this finding is unclear. The accumulation of glycogen particles in nerve fibers was less than that found in muscle fibers. These morphologic differences between muscle and peripheral nerve fibers may represent an intrinsic difference between the two tissues; glycogen turnover may be faster in muscle than in nerve cells.