Embryonic development of the kidney

Abstract

The mammalian kidney functions as a key regulator of water balance, acid–base homeostasis, maintenance of electrolytes, and waste excretion. The performance of these activities depends on the development of specific cell types in a precise temporal and spatial pattern, to produce a sufficient number of nephrons. Over the past several decades, considerable advances have been made in understanding the molecular basis for this developmental program. Defects in this program result in congenital anomalies of the kidney and urinary tract, which are the leading causes of chronic kidney disease and renal failure in children. These developmental disorders range from renal malformations, such as renal aplasia (absence of the kidney), dysplasia (failure of normal renal differentiation), and hypoplasia (smaller kidneys), to urinary tract abnormalities such as vesicoureteral reflux and duplicated collecting systems. This chapter describes the embryology of the kidney and urinary tract, as a means to understand the developmental origins of these disorders.