Clinical impact and biological basis of renal malformations.

Little is understood regarding the pathogenesis of human renal malformations. These disorders include the total absence of renal tissue (or renal aplasia) and organs that contain undifferentiated kidney cells (or renal dysplasia). Various lines of evidence from animal studies suggest that kidney malformations can be generated by (1) the mutation of master genes expressed during nephrogenesis, (2) the prenatal obstruction of the urinary tract, and (3) also by teratogens. Although the majority of human renal malformations occur sporadically, some are familial and would thus seem to have a genetic basis. It is possible but unproven that some sporadic cases may represent new mutations. A understanding of the biology of normal and abnormal nephrogenesis will ultimately lead to earlier diagnoses of renal malformations and will make it possible to conceive of therapeutic strategies that may enhance the differentiation and survival of metanephric precursor cells.