Unilateral Renal Hypoplasia
	1. Severe Defect in Nephron Number    Unilateral hypoplasia= 1% of the population.    Perhaps asymmetries seen by ultrasound of our patients in the hospital are more subtle forms of unilateral hypoplasia. 2.  Bilateral disease= functional for 5-10yrs; then constitutes 20% of the juvenile population on dialysis.