Renal dysplasia/hypoplasia

Abstract

Congenital renal hypoplasia/dysplasia refers to the end result of a variety of pathogenic mechanisms that disturb the primary induction of metanephric progenitor cells (renal agenesis), dysregulation of nephron number (disorders of progenitor pool size or ureteric bud branching), aberrant progenitor cell differentiation (dysplastic tissue elements), disturbance of the renal vasculature (causing tubular dysgenesis), organ structure (multicystic/dysplastic kidney), and tissue migration (horseshoe kidney, ectopic kidney). Many of these disturbances are linked to mutation of genes in molecular cascades involved in the development of other organs; thus, renal hypoplasia/dysplasia can be seen with a variety of non-renal malformations. It has been useful to assemble large heterogeneous pediatric cohorts under the umbrella term of congenital anomalies of the kidney and urinary tract (CAKUT) as a way to study classification and identification of underlying genes without bias [1]. In this chapter we consider forms of CAKUT associated with reduced functional renal mass at birth.