Medullary Cystic Kidney Disease Type 2 (MCKD2)

What is Medullary Cystic Kidney Disease Type 2 (MCKD2)?

Medullary Cystic Kidney Disease Type 2 is a rare genetic kidney condition that runs in families. The disease causes small cysts to form in the center part of the kidneys called the medulla. Over time, these cysts damage kidney tissue and cause the kidneys to lose their ability to filter waste from your blood.

MCKD2 is caused by mutations in the UMOD gene, which affects how your kidneys handle uric acid. Uric acid is a waste product that normally leaves your body through urine. People with MCKD2 have trouble removing uric acid through their kidneys, which leads to high levels in the blood. This condition often shows up in your 20s or 30s and slowly gets worse over many years.

The disease follows an autosomal dominant pattern, which means you only need one changed gene from one parent to develop the condition. High uric acid levels appear years before significant kidney damage occurs. This makes early blood testing important for catching the disease and protecting your kidney function.

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Symptoms

Frequent urination, especially at night
Excessive thirst
Fatigue and weakness
High blood pressure
Gout or joint pain from high uric acid
Loss of appetite
Nausea
Swelling in feet and ankles
Changes in urine output

Many people with MCKD2 have no symptoms in the early stages. The condition often develops slowly over 10 to 20 years. High uric acid levels may be the only sign for years before other symptoms appear. Some people only discover they have MCKD2 through routine blood work or family history screening.

Causes and risk factors

MCKD2 is caused by mutations in the UMOD gene, which provides instructions for making a protein called uromodulin. This protein is made only in the kidneys and helps protect the urinary tract from infection. When the gene is mutated, abnormal uromodulin builds up in kidney cells and damages them. The damaged cells cannot properly move uric acid from the blood into the urine, leading to high serum uric acid levels.

The main risk factor is having a parent with MCKD2, since the condition is inherited. Each child of an affected parent has a 50% chance of inheriting the mutation. There are no lifestyle factors that cause MCKD2. However, once you have the condition, certain factors can make kidney damage worse. Dehydration, high protein diets, excessive alcohol, and medications that stress the kidneys can speed up disease progression.

How it's diagnosed

MCKD2 is diagnosed through a combination of blood tests, family history, genetic testing, and imaging. Blood work showing elevated uric acid levels along with declining kidney function can suggest MCKD2. Your doctor will check serum uric acid, creatinine, and estimated glomerular filtration rate to assess how well your kidneys are working. High uric acid that appears before significant kidney damage is a key clue.

Rite Aid offers testing for serum uric acid as part of our flagship health panel. This test helps monitor kidney health and catch elevated uric acid levels early. Genetic testing can confirm the diagnosis by identifying UMOD gene mutations. Kidney ultrasound or CT scans may show small cysts in the medulla, though these are not always visible. A family history of kidney disease or gout in multiple generations also supports the diagnosis.

Treatment options

Drink plenty of water to stay well hydrated and support kidney function
Limit foods high in purines, such as red meat, organ meats, and certain seafood
Reduce alcohol consumption, especially beer
Maintain a healthy weight through balanced nutrition
Control blood pressure with medication if needed
Take allopurinol or febuxostat to lower uric acid levels
Avoid medications that harm the kidneys, like NSAIDs
Monitor kidney function regularly with blood tests
Dialysis or kidney transplant may be needed in advanced stages

Frequently asked questions

MCKD1 and MCKD2 are both genetic kidney diseases that cause cysts and kidney failure. MCKD2 is caused by mutations in the UMOD gene and features high uric acid levels before kidney failure develops. MCKD1 is caused by mutations in the MUC1 gene and does not typically involve high uric acid. MCKD2 is more common and better understood than MCKD1.

Most people with MCKD2 develop symptoms in their 20s or 30s, though the timing varies. Some people show elevated uric acid levels in their teens or early 20s before any symptoms appear. Kidney function typically declines slowly over 10 to 20 years. Family members may develop symptoms at different ages depending on the specific mutation.

Yes, elevated uric acid is often the first detectable sign of MCKD2. High uric acid levels appear years before significant kidney damage occurs. Regular monitoring of serum uric acid helps track disease progression and guide treatment decisions. This makes uric acid testing important for people with a family history of MCKD2.

There is no cure for MCKD2 because it is caused by a genetic mutation. Treatment focuses on slowing kidney damage and managing symptoms. Medications to lower uric acid, lifestyle changes, and blood pressure control help preserve kidney function. In end-stage kidney disease, dialysis or kidney transplant become necessary.

MCKD2 causes small cysts in the center of the kidneys and progresses slowly. Polycystic kidney disease causes large cysts throughout the kidneys and progresses faster. MCKD2 features high uric acid and gout, while polycystic kidney disease does not. Both are genetic, but they involve different genes and different inheritance patterns.

Yes, if you have MCKD2, your children and siblings should consider testing. Each child has a 50% chance of inheriting the condition. Early detection through uric acid testing and genetic screening allows for early intervention. Family members can make lifestyle changes and start monitoring before symptoms appear.

Yes, diet plays an important role in managing MCKD2. Eating less red meat, organ meats, and shellfish reduces purine intake and helps lower uric acid. Staying well hydrated supports kidney function. Limiting salt helps control blood pressure, which protects the kidneys. A kidney-friendly diet can slow disease progression significantly.

Untreated MCKD2 leads to progressive kidney damage and eventual kidney failure. High uric acid levels can cause painful gout attacks and kidney stones. Blood pressure usually rises as kidney function declines. Most people with untreated MCKD2 eventually need dialysis or kidney transplant, typically in their 40s or 50s.

If you have MCKD2 or a family history of the condition, check uric acid levels at least once or twice per year. More frequent testing may be needed if your levels are high or changing. Regular monitoring helps your doctor adjust medications and catch kidney function changes early. Rite Aid offers convenient testing at Quest Diagnostics locations nationwide.

Yes, high uric acid from MCKD2 can cause gout before significant kidney damage appears. Gout happens when uric acid crystals form in your joints, causing pain and inflammation. Many people with MCKD2 experience gout in their 20s or 30s. Treating high uric acid early can prevent gout attacks and protect your kidneys at the same time.