The pathogenesis of renal dysplasia. I. Quantification of hypoplasia and dysplasia.

In order to assess the relative effects of abnormal ureteric orifice position and abnormal urodynamics on the morphogenesis of hypoplasia and dysplasia in kidneys obtained from infants, we devised a method of quantifying the renal structures. The method was based on radial glomerular counts which ranged from zero to normal (seven to nine), a score for dysplastic structures, and the ratio of normal to abnormal tissues present. These three values, when plotted against each other, correlated closely. The glomerular count, with occasional minor adjustment for inconsistencies, was the best parameter of hypodysplasia. Severe to moderate grades of hypodysplasias fell in the low and middle ranges and hypoplasia through to normal in the highest range. By grading kidneys in this way, we were able to compare the effects of ureteral ectopy and abnormal urinary dynamics on the developing kidney.