kidney disease that scars the kidneys, causing them to lose functionality. Focal and segmental glomerulosclerosis (FSGS; often incorrectly abbreviated as focal sclerosis) is a morphologic pattern of glomerular injury primarily directed at the glomerular visceral epithelial cell (the podocyte) and defined by the presence of. Focal segmental glomerulosclerosis (FSGS) is a histologic pattern of injury in the kidney that may have multiple different etiologies, including genetic diseases, infection, toxins, and obesity, as well as previous injury resulting in hyperfiltration.