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Overview of congenital anomalies of the kidney and urinary tract (CAKUT)

Norman D Rosenblum, MD, FRCP
Section Editors
Tej K Mattoo, MD, DCH, FRCP
Laurence S Baskin, MD, FAAP
Deputy Editor
Melanie S Kim, MD


Congenital anomalies of the kidney and urinary tract (CAKUT) constitute approximately 20 to 30 percent of all anomalies identified in the prenatal period [1]. Defects can be bilateral or unilateral, and different defects often coexist in an individual child.

An overview of CAKUT is presented here. The antenatal screening and postnatal evaluation of infants with CAKUT are discussed in greater detail separately. (See "Evaluation of congenital anomalies of the kidney and urinary tract (CAKUT)" and "Congenital ureteropelvic junction obstruction" and "Primary megaureter in infants and children" and "Ectopic ureter" and "Renal ectopic and fusion anomalies" and "Autosomal recessive polycystic kidney disease in children".)


Because CAKUT play a causative role in 30 to 50 percent of cases of end-stage renal disease (ESRD) in children [2], it is important to diagnose these anomalies and initiate therapy to minimize renal damage, prevent or delay the onset of ESRD, and provide supportive care to avoid complications of ESRD. Patients with malformations involving a reduction in kidney numbers or size are most likely to have a poor renal prognosis [3]. (See 'Renal development and CAKUT' below and "Overview of the management of chronic kidney disease in children".)


Normal embryology — Normal embryologic development of the kidney occurs in three stages (figure 1). Of note, in this discussion, embryonic age begins at conception and not at last menstrual period.

Pronephros – Transient rudimentary and nonfunctioning system that begins in the fourth week of embryogenesis (ie, day 22) and disappears by end of the fourth week (ie, day 28). Degeneration of the pronephros is required for normal kidney development.

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Literature review current through: Nov 2017. | This topic last updated: Aug 29, 2016.
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