ADPKD stands for autosomal dominant polycystic kidney disease, a genetic condition in which fluid-filled cysts grow throughout both kidneys over the course of decades. It affects roughly 1 in 400 to 1,000 people worldwide, making it one of the most common inherited kidney disorders. In the United States alone, about 500,000 people live with some form of polycystic kidney disease, and ADPKD accounts for the vast majority of those cases.
The Genetics Behind ADPKD
“Autosomal dominant” describes how the condition is passed down. You only need one copy of the mutated gene, inherited from one parent, to develop the disease. If a parent carries the mutation, each child has a 50% chance of inheriting it. About 90% of people with ADPKD inherited the mutation from an affected parent, while the remaining 10% developed a brand-new mutation with no family history.
Two genes are responsible for nearly all cases. PKD1, located on chromosome 16, accounts for about 85% of cases and tends to cause more severe disease. PKD2, on chromosome 4, accounts for roughly 15% and generally follows a slower course. A third gene, GANAB, contributes to about 1% of cases and is more associated with liver cysts than kidney cysts.
How Cysts Form and Grow
The PKD1 and PKD2 genes produce proteins called polycystin-1 and polycystin-2, which sit on tiny hair-like structures (called cilia) on the surface of kidney cells. These proteins help the cells sense fluid flow and regulate calcium signaling. When the proteins are defective, cells lose their ability to control growth and fluid balance properly.
Each cyst starts from a single kidney cell that undergoes a “second hit,” a second genetic mutation in its remaining healthy copy of the PKD1 or PKD2 gene. That cell begins dividing uncontrollably and secreting chloride-rich fluid, which inflates the cyst like a balloon. Over time the cyst pinches off from the kidney tubule it originated in and continues expanding on its own. Cysts can form anywhere along the kidney’s filtering tubes but are most common in the collecting ducts, the final stretch where urine is concentrated before leaving the kidney.
Symptoms and Kidney Complications
ADPKD is often silent for decades. Most people don’t notice symptoms until their 30s or 40s, though cysts may be forming much earlier. The most common problems are pain, high blood pressure, and progressive loss of kidney function.
Pain typically comes from enlarged cysts stretching the kidney capsule, cysts bleeding or rupturing, urinary tract infections, or kidney stones. Blood in the urine (hematuria) is another early sign. High blood pressure develops in almost everyone with ADPKD who eventually reaches kidney failure, and it often appears years before kidney function starts declining. Kidney stones are also more common in people with ADPKD than in the general population, partly because the distorted kidney anatomy makes it harder for urine to drain normally.
The pace of kidney decline depends heavily on which gene is involved. People with PKD1 mutations reach end-stage kidney failure at a median age of about 53, while those with PKD2 mutations typically don’t reach that point until around age 73. That’s roughly a 20-year difference in disease trajectory based on genetics alone.
Problems Beyond the Kidneys
ADPKD is a systemic condition, not just a kidney disease. Cysts and connective tissue abnormalities can show up in several other organs:
- Liver cysts: Found in up to 94% of ADPKD patients, making this the most common extra-kidney feature. They rarely cause liver failure but can cause discomfort or abdominal fullness when large.
- Brain aneurysms: About 8% of people with ADPKD have small balloon-like bulges in brain blood vessels. These usually cause no symptoms but carry a risk of rupture, so screening is recommended for those with a family history of aneurysm or stroke.
- Heart valve problems: Mitral valve prolapse occurs in roughly 25% of patients, though it’s usually mild.
- Other cysts: The pancreas (9%), the membranes surrounding the brain (8%), and the seminal vesicles in men (40%) can all develop cysts.
- Hernias: Abdominal wall hernias affect about 10% of patients, likely related to connective tissue changes.
How ADPKD Is Diagnosed
Diagnosis typically starts with an ultrasound, especially for people who have a parent with the condition. The number of cysts needed for a definitive diagnosis depends on your age, because simple kidney cysts become more common as everyone gets older.
For people aged 15 to 39 who are at risk, three or more cysts (in one or both kidneys combined) are enough to confirm the diagnosis. Between ages 40 and 59, at least two cysts in each kidney are required. After age 60, when simple cysts are common in the general population, the bar rises to four or more cysts in each kidney. Genetic testing is available but not always necessary when ultrasound findings are clear-cut and family history is known.
Managing Blood Pressure
Blood pressure control is the single most important factor you can influence to slow kidney damage. The targets for ADPKD are lower than standard blood pressure goals. The 2025 KDIGO guidelines recommend that adults aged 18 to 49 with early-stage kidney disease aim for a home blood pressure reading at or below 110/75 mm Hg, if tolerated. For those 50 and older, the target is a systolic reading (the top number) below 120 mm Hg in clinical measurements. For adolescents with ADPKD and high blood pressure, the goal is at or below 110/70.
These aggressive targets come from trial data showing that tighter blood pressure control meaningfully slows kidney growth and preserves function over time.
Treatment and Slowing Disease Progression
There is no cure for ADPKD, but treatment has advanced significantly. A medication called tolvaptan (brand name Jynarque) works by blocking a hormone receptor that drives cyst growth and fluid secretion. It’s approved for adults at risk of rapid disease progression. Doctors use imaging-based classification systems that compare your total kidney volume to your age to determine whether your disease is progressing fast enough to warrant this treatment. Tolvaptan causes significant thirst and frequent urination, so it requires regular liver function monitoring and a commitment to staying well-hydrated.
For patients who do reach kidney failure, dialysis or kidney transplantation becomes necessary. Transplant outcomes for ADPKD patients are generally favorable compared to other causes of kidney failure.
Diet and Hydration
Keeping sodium intake low helps with blood pressure control and may slow cyst growth. Most guidelines recommend staying under 2.3 grams of sodium per day, which translates to about 6 grams of table salt. If you’re taking tolvaptan, some guidelines suggest an even stricter limit of 2.4 grams of sodium or less.
Higher water intake is also encouraged, particularly in earlier stages of the disease. The reasoning is that staying well-hydrated suppresses a hormone called vasopressin, which promotes cyst growth. Guidelines from various countries suggest anywhere from 2 to 4 liters of water per day, depending on your kidney function and climate. One practical formula calculates your daily water need based on how much solute your kidneys need to clear: divide your 24-hour urine solute load by 280, then add half a liter for water lost through breathing and sweat. For many people, this works out to 3 to 4.5 liters per day. Spreading water intake throughout the day, including before bed, helps keep vasopressin levels consistently low.