Focal glomerular sclerosis.

There seems to be little doubt that FGS is a nonspecific lesion that represents one way in which the renal glomerulus responds to a variety of injuries. This is illustrated by the large number of diverse conditions with which the lesion is associated including various forms of glomerulonephritis, pyelonephritis, hereditary nephritis, and heroin usage. Nevertheless, there remains a relatively large isiopathic group which, though possibly heterogeneous, displays a number of characteristic clinical and pathologic features including the following: 1. Steroid-resistant nephrotic syndrome; 2. Hematuria and hypertension; 3. Normal serum complement; 4. Progressive renal insufficiency; 5. Typical pathologic lesion most common in or restricted to juxtamedullary cortex; 6. Absence of clearly defined evidence of immune complex deposition by immunofluorescent or electron microscopic studies; 7. Recurrence of the lesion following renal transplantation. The pathogenesis of these changes is unclear, the evidence for an immune complex mechanism meager, and the suggestion that the disease is mediated by a humoral mechanism remains to be explored. The potential recurrence of this lesion in the transplanted kidney affords a unique opportunity to study the disease early in its course by a variety of techniques that may help to clarify this still poorly understood entity.