What is congenital anomalies of the kidney and urinary tract (CAKUT)?

Congenital anomalies of the kidney and urinary tract (CAKUT) are a group of conditions where the urinary tract, including the kidneys, do not develop properly before birth.

The urinary tract is the system that gets rid of waste and fluid from our body in our urine. It includes the kidneys, bladder and the tubes that carry urine, which are the ureters and urethra.

CAKUT includes conditions where the kidneys don’t develop normally, such as:

Kidney hypoplasia, where one or both kidneys are smaller than normal

Kidney dysplasia, where the kidneys have developed abnormally

Kidney agenesis, where one or both kidneys are missing

Duplex kidney, where the kidney is abnormally shaped and usually has two ureters

Horseshoe kidney, where both kidneys are fused together and form a horseshoe shape

CAKUT also includes conditions where the the rest of the urinary tract has not developed as expected, such as:

Posterior urethral valves (PUVs), where flaps of tissue block the urethra, which is the tube that carries urine from the bladder

Conditions where there are blockages in the ureter, such as a pelvi-ureteric junction obstruction or ureterovesical junction obstruction

Vesicoureteral reflux, where there is a backflow of urine into the ureters from the bladder

Ectopic ureter(s), where one or both ureters do not connect normally to the bladder

What are the causes of CAKUT?

CAKUT has several causes. This includes genetics, which are changes in our DNA, and can be inherited.

Factors which affect the environment surrounding the baby during development can also increase the risk of CAKUT, such as if the baby’s mother has diabetes, chronic kidney disease, cancer, is living with obesity, takes certain medications that are harmful to the kidneys, or has poor nutrition.

Patients with certain conditions also have a higher risk of having CAKUT, including renal coloboma syndrome, 17q12 deletion syndrome, or Down syndrome.

What are the symptoms of CAKUT?

Symptoms of CAKUT will depend on the specific condition. Symptoms can include:

Repeated urinary tract infections (UTIs)

Problems urinating

A build-up of urine, which can damage the kidneys and other parts of the urinary tract
Kidney failure

How is CAKUT diagnosed?

Sometimes CAKUT can be diagnosed before birth using an ultrasound scan. Additional ultrasound scans after the baby is born will allow the doctor to see the urinary tract in more detail and look for any visible blockages.

Special medical images can also be used to look at urine flow through the urinary tract to identify any problems.

CAKUT treatments

Treatments for CAKUT will depend on the specific condition but can include:

Antibiotics to treat UTIs

Surgery on the urinary tract

In some cases, patients develop kidney failure, for which treatment options include transplant or dialysis.

References

Stonebrook, E. Hoff, M. and Spencer, J. D. Congenital Anomalies of the Kidney and Urinary Tract: A Clinical Review [online]. 2019. Curr Treat Options Pediatr. 11;5(3):223–235. [Accessed 11 March 2026]. Available from: <PMCID: 32864297>

Tidy, C. Congenital urogenital malformations [online]. Patient.info, Navigate Health Ltd: London, UK; [Accessed 11 March 2026]. Available from: Congenital Urogenital Malformations information | Doctor

Rabinowitz, R. and Cubillos, J. Renal Anomalies [online]. Manual, Merck & Co, Inc., Rahway, NJ, USA; Sept 2024 [Accessed 11 March 2026]. Available from: Renal Anomalies - Pediatrics - MSD Manual Professional Edition

Mahmoud, A. H., Talaat, I. M., Tlili, A. and Hamoudi, R. [online]. 2024. Front Med. 15;11:1384676. [Accessed 11 March 2026]. Available from: <PMCID: 39076761>

Jayanthan, S. S., Ganesh, R., Karunakaran, N., Mukuntharajan, T., Manodoss, N., Dedhia, K. and Nadanasadharam, K. Renal Coloboma Syndrome—An Autosomal Dominant Genetic Disorder [online]. 2023. Indian J Radiol Imaging. 6;33(2):260–263. [Accessed 11 March 2026]. Available from: <PMCID: 37123577>

Mitchel, M. W., Moreno-De-Luca, MD, D., Myers, S. M., Levy, R. V., Turner, S., Ledbetter, D. H. and Martin, C. L. 17q12 Recurrent Deletion Syndrome [online]. 2025. GeneReviews. [Accessed 11 March 2026]. Available from: <PMCID: 27929632>

Leskur, M., Leskur, D., Marijan, S., Minarik, L. and Lozić, B. Congenital Anomalies of the Kidney and Urinary Tract in Down Syndrome: Prevalence, Phenotypes, Genetics and Clinical Management [online]. 2025. Genes (Basel). 20;16(3):245. [Accessed 11 March 2026]. Available from: <PMCID: 40149397>

Reviewed May 2026