Renal Agenesis

Renal agenesis is the failure of embryonic development of one or both kidneys. Unilateral renal agenesis is usually asymptomatic and does not affect life, whereas bilateral forms are usually fatal. In bilateral agenesis, kidney transplantation is the only effective therapy.

Renal Agenesis

What is renal agenesis?

During embryogenesis, the kidneys gradually develop in a healthy embryo. This development takes place on the basis of the intermediate mesoderm and includes the separate formation of the pro-kidneys, meso-kidneys and post-kidneys. The individual development steps are highly complex. In early embryonic development, three kidneys are created one after the other. The last developed system takes over the function of the kidneys, while the other two systems recede or are incorporated into the urogenital tract. See definitionexplorer for Cachexia Definitions.

The development extends from the 22nd day of pregnancy to about the fifth week of pregnancy. If an error occurs during fetal kidney development, it can cause renal agenesis. With such renal agenesis, one or even both kidneys fail to develop. If only one kidney is affected, doctors speak of unilateral renal agenesis. If both kidneys are affected, there is bilateral renal agenesis. Sometimes there is also talk of anephria, which is usually fatal.


The causes of renal agenesis lie in embryogenesis. Up to the fifth week of pregnancy, the kidney buds are either incorrectly differentiated or not differentiated at all. Renal agenesis has been diagnosed in about 1 in 800 to 1100 live births. Boys were affected more often than girls. A familial cluster could not be determined. Presumably there are no genetic dispositions associated with the phenomenon.

It is therefore unlikely that renal agenesis can be passed on. The lack of development of one or both kidneys can be traced back to an abnormal development of the primitive ureter rather than to genetic causes. The metanephrogenic blastema of those affected is also affected by an abnormal development, which is also causally related to agenesis. What exactly causes the abnormal development of the ureter and the blastema has not been finally clarified. There is currently speculation about spontaneous gene mutations caused by environmental toxins.

Symptoms, Ailments & Signs

The unilateral absence of the kidneys is usually compensated during kidney development by the enlarged development of the second kidney. Clinically, there are no clinical symptoms if the kidneys are missing on one side, as long as the second kidney is fully functional. Accompanying malformations of the urinary organs occur, such as those of the bladder and the ureter.

Under certain circumstances, recurrent urinary tract infections can also occur, with which the malformations are causally related. Bilateral renal agenesis is also usually associated with other malformations. Because the malformations in this form of agenesis, for example, often correspond to multiple malformations of the lungs and without the kidneys, the waste products cannot be removed from the blood in the long term, even with the help of dialysis, bilateral agenesis of the kidneys is usually not compatible with life. In addition to a lack of vitamins and erythropoietin, there are symptoms of poisoning.

Diagnosis & course of disease

Renal agenesis is usually diagnosed prenatally using sonography. If the unilateral abnormal development is only discovered postnatally, it is usually an incidental sonographic finding, since the patients are asymptomatic. Kidney function can be checked by examining urine and serum.

It is necessary to determine the creatinine and urea levels as well as the electrolyte level. Potassium, sodium and chlorine play a primary role in the electrolyte level. Unilateral renal agenesis is usually asymptomatic and hardly affects the affected person. Bilateral forms of renal agenesis are associated with a fatal prognosis.


As already mentioned, unilateral renal agenesis usually causes no symptoms because one kidney takes over the tasks of both kidneys. However, the risk of complications is increased when diseases of the urinary tract occur. If both kidneys are missing, survival is not possible at all. Often the missing kidney is not even noticed by those affected.

However, in female patients, a genital malformation is observed in 75 to 90 percent of cases. If unilateral renal agenesis is discovered as a result of an incidental finding, constant medical monitoring is still necessary in order to rule out complications in advance. The diseases that could cause a loss of kidney function are always dangerous.

This often leads to the patient having to undergo dialysis or even total kidney failure, which can then only be treated with the help of a kidney transplant. Therefore, for a patient with unilateral renal agenesis, there is a need for self-monitoring for related symptoms and for measures to prevent diseases of the lower urinary tract.

Appropriate hygiene measures such as urinating after coitus or, in the case of women, wiping the urethra in the direction of the anus are required for this. If signs of a urinary tract infection appear, an immediate blood and urine test is required. The same applies if there is an unclear feverish infection. An infection of the urinary tract must be treated immediately with antibiotics.

When should you go to the doctor?

Parents whose child has been diagnosed with renal agenesis must consult their doctor closely. The absence of one or both kidneys is a serious condition that must be treated as part of an organ transplant. Accordingly, the affected children cannot leave the hospital after birth, but must be closely monitored and cared for. After a procedure, the child should be carefully observed. Signs that the body is rejecting the donor kidney should be reported to the doctor treating you immediately.

The child must be taken to a hospital immediately so that further examinations and, if necessary, another operation can be initiated. With unilateral renal agenesis, a doctor should be consulted if the child shows signs of severe discomfort. Inflammation of the urinary tract and abdominal injuries require immediate evaluation by a specialist, as there is a risk of inflammatory kidney damage. In addition to the general practitioner, both forms of renal agenesis are treated by an internist. At the same time, parents and children should take advantage of therapeutic support.

Treatment & Therapy

Complete anephria can only be corrected by organ transplantation . Unilateral renal agenesis usually does not need to be treated, since the enlarged, second kidney satisfactorily replaces the function of the missing kidney. A complication is associated diseases that impair the function of the remaining kidney. Functional kidney diseases make patients with unilateral renal agenesis, for example, mandatory dialysis and become life-threatening for those affected more quickly than for people without a missing kidney.

For this reason, all diseases of the urinary tract and abdominal injuries must be monitored with care and caution in order to prevent functional kidney disease. Those affected by unilateral renal agenesis are therefore asked by the doctor to observe themselves carefully if they develop inflammation of the urinary tract, for example, since such inflammation can lead to inflammatory kidney damage.

Hygiene measures for the prophylaxis of urinary tract infections are crucial preventive measures that the patient can use to protect his remaining kidney. As soon as the first signs of a urinary tract infection or another infection of unclear origin appear, patients with renal agenesis must immediately have these symptoms clarified by a doctor via blood analyzes and urine samples before their unilateral kidney can be damaged. Antibiotic therapy must take place as soon as possible against inflammatory diseases of the urinary tract.

Outlook & Forecast

The prognosis of renal agenesis depends on the extent of the individually occurring symptoms. Decisive for the further course is the clarification of whether one or both kidneys are affected by the health problems. A large number of those affected are diagnosed in the womb. Doctors can therefore react promptly and comprehensively to possible complaints because they are prepared for health irregularities.

With an unfavorable course of the disease, both kidneys of the patient are affected. In these cases, a kidney transplant is necessary. The transplantation of a donor organ is associated with numerous complications and side effects. Lifelong medical care takes place so that any complaints can be influenced immediately.

In some patients, the disease goes undetected for a long time. The existing symptoms are minor or the person concerned experiences freedom from symptoms. This is often the case when renal agenesis affects only one kidney. In this case, the healthy kidney takes over the tasks for both organs, so that often no impairments are noticed in everyday life.

In principle, the risk of infection is increased in people with the disease. If complications or other diseases occur, there is a risk of organ failure. Once the kidney’s ability to function is impaired, a life-threatening condition develops.


The causes of renal agenesis are still unknown. It is therefore difficult to prevent this malformation of the kidneys. Since genetic mutations due to environmental toxins are now associated with the deformity, avoiding contact with toxins can sometimes be a preventive measure. On the other hand, environmental toxins cannot be completely avoided during pregnancy under any circumstances.


In most cases, those affected with renal agenesis only have very few and only very limited measures or options for direct follow-up care. Those affected should therefore contact a doctor as soon as the first symptoms or signs of the disease appear, so that there are no further complications or complaints. A self-healing of renal agenesis cannot occur.

This disease does not always need to be treated, although regular check-ups and examinations by a doctor are very important. The kidneys and urinary tract in particular should be checked regularly by a doctor. Regular blood tests should also be carried out.

In some cases, renal agenesis can cause infection or inflammation of the urinary tract or kidneys, requiring treatment with antibiotics. Those affected should always observe the correct dosage and regular intake, whereby alcohol should be avoided during the cure.

In general, with this disease, a healthy lifestyle with a healthy diet can have a very positive effect on the further course of the disease. As a rule, this disease does not reduce the life expectancy of those affected.

You can do that yourself

Unilateral renal aganesia does not require treatment. The child can grow up with one kidney without any problems, without expecting any complications. Nevertheless, parents should watch out for unusual symptoms and report them to the doctor if necessary.

However, should symptoms occur that indicate a kidney function disorder, the medical emergency service must be contacted. In the case of bilateral renal aganesia, the child is not viable without dialysis. The most important self-help measure is to deal with the fears associated with such a serious condition. After a kidney transplant, the child must be under constant observation so that the emergency doctor can be called immediately in the event of complications. Parents can also organize outpatient care to support them in caring for the child.

In addition to the symptomatic treatment, the parents should visit a specialist center for internal diseases and learn more about renal aganesia there. In general, knowledge about the disease helps to take the right measures in an emergency. As the child grows up, they need to be made aware of their suffering. The parents can take on this task themselves and inform the child about the disease together with the responsible nephrologist or general practitioner.