What is Congenital Kidney Disease?
Congenital kidney disease means being born with differences in the kidneys or urinary tract - such as a single kidney, reflux, or a blockage. These differences happen during pregnancy and can affect how well the kidneys work.
Doctors often group these conditions under the name CAKUT (Congenital Anomalies of the Kidney and Urinary Tract). While the term may be unfamiliar, it describes one of the leading causes of chronic kidney disease and kidney failure in children and young adults.
Common Conditions
Families usually know their child's diagnosis by its specific name. These are some of the most common types of congenital kidney disease:
Hydronephrosis
Swelling in the kidney because urine cannot drain properly
Vesicoureteral reflux (VUR)
Urine flows backward from the bladder to the kidneys.
Dysplastic or hypoplastic kidneys
Kidneys that didn't develop normally or are too small.
Single kidney (renal agenesis or kidney removal)
A child is born with one functioning kidney or has one removed early in life.
Multicystic dysplastic kidney
A kidney made up of fluid-filled sacs instead of working tissue.
Posterior urethral valves (PUV)
A blockage in boys that stops urine from flowing out normally.
Read our condition guides
Diagnosis
Kidney differences can be found:
Before birth (prenatal ultrasound at 16-20 weeks)
After birth (due to UTIs, abnormal bloodwork, or imaging)
Doctors may use:
Ultrasounds to check kidney size and shape
Urine tests for infection or protein
Blood tests for kidney function
Causes
Kidney differences can be found:
Genetic changes or family history
Maternal health during pregnancy (e.g. diabetes)
Certain medications during pregnancy
Parents did nothing wrong. Most cases occur simply due to how the baby developed.
How It Affects Children
Every child is different. Some live healthy lives with only monitoring. Others may:
Experience urinary tract infections (UTIs)
Develop high blood pressure
Slowly lose kidney function over time
In fact, congenital kidney disease is responsible for 40-50% of all kidney
Failure in children. Early detection and monitoring make a big difference.
Adults Living With Congenital Kidney Disease
Although these conditions start before birth, many people are not diagnosed until adolescence or adulthood. Some only discover it after developing high blood pressure, abnormal labs, or through imaging for another reason. Signs it may still affect you as an adult:
Frequent UTIs in childhood
Only one kidney (or history of kidney removal)
High blood pressure at a young age
Elevated creatinine or low eGFR
Past diagnoses like reflux, PUV, or hydronephrosis
If this sounds familiar, talk to a nephrologist - especially if you have never had one follow your kidney health.
Treatment and Management
Congenital kidney differences cannot be reversed - a kidney that did not form typically cannot be remade. However, treatments and interventions can support and protect kidney function over time. Care focuses on monitoring, managing risks, and supporting overall health.
Mild cases -> regular monitoring
Moderate cases -> surgery for blockages or reflux, bladder training, catheterization, and growth support
Severe cases -> frequent lab and blood pressure checks, and kidney replacement therapy such as dialysis or transplant, if needed
The challenge today is that there are limited therapies available to support kidneys and slow damage from getting worse. This is why KidneyFuture was created - to push for earlier action and better treatment options in the future.
CAKUT, explained properly
Most families meet this word in one of two ways. Either a sonographer goes quiet during a routine pregnancy scan and something gets described as “a bit dilated,” or a baby who seemed entirely well turns out, after a urine infection or a scan for something else, to have a kidney that did not form the way it was supposed to.
Either way, you are usually handed a term nobody explains: CAKUT. It stands for congenital anomalies of the kidney and urinary tract. That is not a single diagnosis. It is a category — an umbrella covering a wide range of differences in how the kidneys, ureters, bladder or urethra formed before birth. Two children can both “have CAKUT” and be facing entirely different futures.
This is the single most useful thing to understand early, because it changes what you should be asking. “What is CAKUT?” has no answer that will help you. “Which one does my child have, and what does that specific one usually mean?” does.
The conditions under the umbrella
These are the ones families most often hear. The names are unfamiliar, but each describes something fairly simple.
Hydronephrosis — swelling of a kidney because urine is not draining away as freely as it should. This is by far the most common thing picked up on a prenatal scan, and it is the reason for a great many anxious pregnancies. It is a finding rather than a diagnosis: it tells you urine is backing up, not why. Mild cases frequently settle on their own as a baby grows, which is why the usual response is another scan rather than immediate action.
Renal agenesis — a kidney did not form at all. When it is one kidney, children very often grow up healthy, with the remaining kidney taking on the work of two.
Renal hypoplasia and dysplasia — a kidney formed, but small (hypoplasia) or with disorganised internal structure (dysplasia). Dysplastic kidneys often do less work than their size suggests.
Multicystic dysplastic kidney — a kidney made up largely of cysts, which does not function. It commonly shrinks over time on its own. Attention usually shifts to protecting the other kidney.
Vesicoureteral reflux — urine travels back up from the bladder toward the kidney instead of only flowing down. It is graded by severity, milder grades often resolve as a child grows, and its main significance is that it can carry infection upward to the kidney.
Posterior urethral valves — extra tissue partly blocking the urethra, so the bladder cannot empty properly. It occurs in boys, it is one of the more serious conditions in this group, and it is usually acted on early because the pressure that builds up behind an obstruction is what damages kidneys.
Ureteropelvic junction obstruction — a narrowing where the kidney meets the ureter, causing urine to pool. Some cases are watched; some are repaired surgically.
Duplex or duplicated collecting system — a kidney drained by two ureters instead of one. Many people have this and never know. Sometimes it comes with reflux or obstruction, which is what actually needs attention.
Horseshoe and ectopic kidney — kidneys fused together, or sitting somewhere other than their usual position. Often found incidentally and often uneventful.
Why it is worth taking seriously even when your child seems fine
Congenital kidney differences are the leading reason children develop chronic kidney disease. That sentence frightens people, and it should be read carefully, because it is a statement about a population and not a prediction about your child. Plenty of children with CAKUT have entirely ordinary childhoods and normal kidney function throughout.
But kidneys are quiet organs. They lose capacity without symptoms, sometimes over years, and a child can look and feel completely well while something is changing slowly underneath. That is the honest reason for the appointments that feel unnecessary. Monitoring is not because something is expected to go wrong. It is because if it starts to, the window to act well is much wider when you catch it early.
What monitoring actually involves
For most families it is undramatic and stays that way: blood pressure, because kidneys and blood pressure affect each other in both directions; a urine test, mainly for protein, which can be an early sign a kidney is under strain; a periodic blood test to estimate how well the kidneys are filtering; attention to growth, which kidney function can influence in children; and imaging at intervals your team will set.
Appointments often thin out as a child gets older and things stay stable. That is a good sign, not a discharge.
The part nobody warns you about
CAKUT does not stop being relevant at eighteen. The most fragile moment in many people’s care is the handover from paediatric to adult services — a familiar team is replaced by an unfamiliar one, at exactly the age when someone is leaving home, and a great many young adults quietly fall out of follow-up there and are not seen again until something has already changed.
If your child is approaching that age, it is worth asking their team directly how transition is handled and who will be responsible afterwards. It is the single most useful question we know of at that stage, and it is very often nobody’s job to raise it.
Questions worth taking to your next appointment
These are the ones families tell us they wish they had asked sooner.
— Which specific condition does my child have, and how is it spelled?
— Is one kidney affected, or both?
— Is this something you expect to improve, stay the same, or need watching for change?
— What would make you want to see us sooner than the next scheduled appointment?
— What should we do about fevers or suspected urine infections, and how quickly?
— Who is responsible for my child’s kidney care as they move into adult services?
A note on what this page is
This is general education, not medical advice, and it cannot account for your child’s particular situation. Your own team knows things about your child that no website does. Use this to understand what you are being told and to walk in with better questions — and if anything here conflicts with what your clinician has said, go with your clinician, and please tell us at [email protected], because it means we have written something badly.
KidneyFuture is an official program of CAKUT Foundation Inc., a registered 501(c)(3) tax-exempt nonprofit organization (EIN: 39-3322233). We are dedicated to uniting families, clinicians, and researchers to transform outcomes for those born with kidney disease.
The information on this site is for general educational purposes only and is not medical advice. Always seek the advice of your physician or another qualified health provider with any questions about a medical condition.
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CAKUT Foundation Inc. (dba KidneyFuture)
1201 Seven Locks Rd, Ste 360, Rockville, MD 20854
Phone: +1 202-630-0043
Email: [email protected]
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