Renal histology in two adult patients with type I glycogen storage disease.

Two adult patients with type I glycogen storage disease (I-GSD) had chronic renal disease with heavy proteinuria. Renal biopsies showed focal glomerular sclerosis, interstitial fibrosis, tubular atrophy or vacuolation, and prominent arteriosclerosis. Marked glomerular hypertrophy was demonstrated histometrically. Oil red O staining in one patient revealed numerous lipid deposits in the glomerular mesangium, tubular epithelial cells and interstitium. Electron microscopy in the other patient revealed diffuse thickening of the glomerular basement membrane (GBM) and lipid droplets within the mesangium. The glomerular hypertrophy, thickening of the GBM, and subsequent sclerosis were similar to those in insulin-dependent diabetes mellitus. These findings may explain the similarities between the natural histories of renal involvement in the two disorders. Particularly, glomerular hypertrophy may be a key step leading to glomerular sclerosis, which is the predominant finding I-GSD. Hyperlipidemia, which is commonly seen in I-GSD, may also accelerate the glomerular sclerosing process.