# Polycystic kidney disease
What is it
Polycystic kidney disease is an inherited disorder in which many fluid-filled sacs (cysts) form in the kidneys. These cysts grow gradually and can damage normal kidney tissue, causing the kidneys to lose function. There are two main forms: the autosomal dominant form (ADPKD), which is most common, and the autosomal recessive form (ARPKD), which is rarer and usually develops at a younger age.
In the dominant form, people inherit the gene from one parent. In the recessive form, both parents must pass on the gene. The disease is caused by mutations in genes that are important for the structure and function of the kidneys, particularly the PKD1 gene.
The cysts are not malignant and originate from the kidney tissue itself. However, as they grow and multiply, more of the kidney is gradually damaged. Eventually, the kidneys can no longer do their job: waste and fluid cannot be properly removed from the body.
Causes
Polycystic kidney disease is caused by inherited mutations in specific genes. These are natural changes in DNA that a person has from birth. These mutations affect how cells in the kidneys grow and organize themselves.
In the dominant form, only one mutation (from one parent) is enough to cause the disease. In the recessive form, mutations from both parents are needed. Parents can be carriers without being sick themselves.
The exact reason why these mutations cause cysts is not yet fully understood. Research shows that they affect how kidney cell functions work, such as how water and waste are processed. Inflammation in the kidneys also plays a role.
It is important to know: you do not get this disease because you did something wrong. It is not the result of lifestyle, diet, or infection.
How the disease progresses
Polycystic kidney disease usually progresses gradually over decades, although the speed varies from person to person.
In the dominant form, cysts may already be present in childhood, but symptoms usually do not develop until the thirties to fifties. The disease progresses slowly: the number and size of cysts increase, causing more and more kidney tissue to be damaged. This process can take place for years before someone notices that kidney function is declining.
In the recessive form, symptoms usually appear earlier, sometimes in childhood or early adulthood. The disease usually progresses faster here.
In both forms, people usually follow a course of gradual loss of kidney function. The kidneys filter less well. This can eventually lead to kidney failure (end-stage kidney disease), in which the kidneys can barely do their job anymore. This does not always happen: some people maintain reasonable kidney function for a long time.
When kidney failure occurs, replacement treatments such as dialysis or kidney transplantation are needed. Some patients can live well for years or decades with dialysis or after transplantation.
Symptoms by phase
**Early phase (no or minimal symptoms)**
Many people do not know for a long time that they have polycystic kidney disease. The disease is sometimes discovered by chance during imaging for another purpose. Sometimes children from families with the disease inherit the gene but feel completely healthy.
**Phase with mild symptoms**
As cysts grow, initial complaints may develop:
- Pain in the back or flanks (sometimes dull, sometimes sharp)
- Blood in the urine (sometimes visible, sometimes only found on examination)
- High blood pressure (often one of the first symptoms)
- Increased frequency of urinary tract infections
**Phase with progressive loss of kidney function**
As kidney function declines (measured by kidney function tests), more complaints may develop:
- Fatigue and concentration problems (due to waste products in the blood)
- Nausea
- Reduced appetite
- Fluid retention (swelling in legs, face)
- Frequent urination at night, especially at night
- Anemia (low blood count)
**End stage (kidney failure phase)**
When the kidneys function very poorly:
- Severe fatigue
- Persistent nausea
- Breathing problems or shortness of breath
- Skin itching
- Changes in taste
- Severe fluid retention
What it means for daily life
Polycystic kidney disease can affect life in different ways, but this is very personal and depends on how quickly the disease progresses.
**In the early stage**
Many feel barely limited and can lead their normal lives. But some have regular back pain that affects their activities. Regular check-ups with a nephrologist are necessary, because blood pressure and kidney function must be monitored closely.
**As symptoms increase**
Fatigue can make work or household tasks more difficult. Higher blood pressure must be treated, which means medication is needed. Dietary restrictions may be necessary — for example less salt, sometimes less protein or potassium. Regular visits to the nephrologist and possibly more tests are part of it.
Emotionally, knowing that you have a chronic, progressive disease can be burdensome. Worries about the future, fear of dialysis or transplantation, and uncertainty can play a role.
**In later stages**
If kidney failure is threatened or present, life can change considerably. Dialysis patients must go to the hospital several times a week — home dialysis is also possible, but requires training and discipline. It limits mobility and activities. Dietary rules become stricter.
After transplantation, many people can have more freedom, but immunosuppressants (medications to prevent rejection) are needed for life, and regular check-ups remain essential.
Family and partners can also be burdened by care and support roles. For people with hereditary burden, advice regarding genetic counseling is important before they have children.
Outlook
The outlook for polycystic kidney disease is very diverse. Some general points:
**Disease progression and duration**
The dominant form is usually less aggressive than the recessive form. Many patients with ADPKD retain usable kidney function for decades. Some never reach complete kidney failure. Others develop problems later in life.
The recessive form usually progresses more rapidly and causes serious problems earlier.
With modern treatment and control of blood pressure and other complications, the rate of decline can be slowed. Research continues into new medications and therapies.
**Survival rates**
At the population level, half of patients with ADPKD reached kidney failure around the 60th to 70th year of life around 2010. However, this is an average; individual experiences vary greatly. For the recessive form: kidney failure occurs much earlier in life, sometimes in childhood or teenage years.
These figures tell you nothing about your personal situation. Much depends on your genes, how quickly cysts grow, how well your blood pressure is controlled, and other factors.
**Available treatments**
If kidney failure occurs, kidney replacement therapies are available: dialysis (both in hospital and at home) and kidney transplantation. With these, people can live well for years or decades, although it requires adjustment.
For complications such as infections, bleeding, or pain, treatment exists.
Research into medications that can slow or halt cyst formation is ongoing. Some medications are already being used and studied for their value.
Frequently asked questions
**Can I pass polycystic kidney disease to my children?**
Yes, if you have the dominant form, there is a 50% chance that each child will inherit the gene and possibly become ill. In the recessive form: both your partner and you must be carriers, otherwise your children will not inherit the disease. Genetic counseling can help you better understand your risk and options.
**How is the disease diagnosed?**
Usually with imaging: ultrasound or CT scan of the kidneys. In addition, blood tests (kidney function) and urine samples. If there is doubt, genetic testing can help.
**Does treatment differ between the two forms?**
Yes, the recessive form more often causes earlier kidney failure and certain additional problems. The speed also varies. The basic approach (blood pressure control, monitoring) is similar, but the treatment plan is adjusted to the individual disease and progression.
**Can I still exercise and move normally?**
This depends on how far the disease has progressed and how you feel. In early stages, many people can move normally. A doctor can provide advice on what is safe. Very strenuous exertion can sometimes cause problems in advanced disease.
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_This information never replaces a doctor's judgment. Always discuss your situation with your own healthcare provider._