Table 4.

Differential diagnostic characteristics of primary FSGS, genetic FSGS, maladaptive FSGS, and FGGS

	Primary FSGS	Genetic FSGS	Maladaptive FSGS	FGGS
Clinical	NS	NS common in childhood, less common in adults	Nephrotic- or subnephrotic-range proteinuria without NS	Variable proteinuria, usually subnephrotic
LM	FSGS	FSGS	FSGS	FGGS
	Often no other damage (unless late in disease course)	FGGS common in adult-onset, uncommon in juvenile forms	Often perihilar	No FSGS
	Glomerulomegaly uncommon		Other signs of scarring	No glomerulomegaly
			FGGS in many glomeruli	Ischemic glomerulia
			Glomerulomegaly common	Associated with tubulointerstitial fibrosis, vascular sclerosis
EM	Diffuse FPE (>80%)	Variable (diffuse or segmental) FPE, characteristic features in some mutations	Segmental FPE	Minimal or no FPE in unaffected glomeruli

NS, nephrotic syndrome.

^aCharacterized by thickening and wrinkling of the GBM and distention of the Bowman space.