[Conceptual review of simple renal ectopy and suggestion of a unifying embryogenetic hypothesis]

Proposal for a conceptual review of the theories currently used to explain the pathogenesis of single kidney ectopia. The inner mechanisms which generate this frequent anomaly in the positioning and rotation of the kidneys are far from being understood. Based on a critical review of the literature and our own observational findings, we believe the single kidney ectopia is a time-dependent embryo-development change model which can be used as a ¿chronopathy¿ paradigm.