abnormal kidney development abnormal nephrogenic zone morphology 2011-10-12T03:48:15Z MP:0011334 MPheno.ontology any structural anomaly in the region found at the periphery of the developing metanephros within which the metanephric mesenchyme aggregates around the tips of the ureteric tree to form the nephrons; in rodents including mice, this region normally disappears within the first postnatal week when nephrogenesis ceases and only mature nephrons are present; in humans, it is lost by 36 weeks of gestation csmith