Patients present with proteinuria and microscopic hematuria.
Hypertension is also common.
The pathogenesis of the sclerosing lesions and their progressive nature are debated. Humans with idiopathic focal segmental glomerulosclerosis initially have a high glomerular filtration rate and evidence of hyperfiltration, suggesting that hyperfiltration and increased intracapillary glomerular pressure may be mediators of this disease. The kidney biopsy in focal segmental glomerulosclerosis demonstrates focal and segmental glomerular sclerosis with capillary loop collapse, hyaline and lipid deposition and often adhesion to Bowman's capsule. The lesions are considered to begin or to be more common near the corticomedullary junction. Deposition of IgM and C3 in the mesangium or in the areas of segmental sclerosis may be seen, but no immune complex deposition is present.