IgA nephropathy (IgAN), also called Berger’s disease, is a kidney disease that develops when a protein called immunoglobulin A builds up in the kidneys. IgA normally helps the body fight infections. But when too much IgA collects in the kidneys’ tiny filters, it can cause swelling and damage. Over time, this can make it harder for the kidneys to remove waste and extra fluid from the blood.

Doctors don’t yet know exactly why this buildup happens in some people and not in others. However, research has found several factors that may raise the risk of developing IgAN. These include genetics, immune system activity, infections, other health conditions, and environmental or lifestyle influences.

Understanding these risk factors can help people with IgAN and their families manage the condition and take steps to protect kidney health.

How IgA Nephropathy Affects the Kidneys

The kidneys are the body’s natural filters. Each kidney has about a million tiny filters called glomeruli. These filters clean the blood by removing waste and sending it out of the body through urine.

In IgAN, IgA proteins get trapped in the glomeruli. This buildup triggers inflammation, which is the body’s way of trying to heal itself. But in this case, the immune system reaction causes more harm than good. The ongoing inflammation scars the filters, making it harder for the kidneys to do their job.

At first, many people don’t notice symptoms. Over time, though, IgAN can cause blood or protein in the urine, swelling in the hands or feet, and high blood pressure. In severe cases, it can lead to ongoing kidney disease or even kidney failure. Let’s discuss some of the factors that raise the risk of IgAN.

1. Family History and Genetics

One of the strongest clues about what causes IgAN is family history. Studies show that certain diseases sometimes run in families, suggesting a genetic link. Having a close relative with IgAN may raise your risk. In more than 10 percent of families affected by IgAN, the condition appears to run in the family. However, some people who carry related genes never develop symptoms.

Scientists have found certain genes that seem to play a role in how the immune system makes and clears IgA. Changes in these genes may cause the body to make abnormal IgA. This IgA is more likely to stick to the kidneys. A study in the Journal of the American Society of Nephrology found that genes linked to the immune system and inflammation may affect who develops the disease and how severe it becomes.

Even though genes can raise the risk, they don’t cause IgAN on their own. Most scientists believe genes interact with infections or changes in the immune system to trigger the disease.

2. Immune System Overactivity

Because IgAN is related to the immune system, many scientists believe it is caused by immune system overactivity. Normally, IgA antibodies help fight bacteria and viruses, especially in the mouth, lungs, and intestines. In IgAN, the immune system may make too much IgA or a form of IgA that clumps together and gets stuck in the kidneys.

Researchers think this may happen because the immune system mistakes the body’s own cells for harmful germs. This kind of overreaction is called an autoimmune response, and it can cause long-term inflammation and scarring in the kidneys.

A study in Frontiers in Immunology found that certain immune cells, called B cells and plasma cells, may make an abnormal form of IgA with missing sugar molecules. This abnormal IgA can clump together and trigger inflammation that damages the kidneys.

3. Infections

Many people first develop symptoms of IgAN after an infection, especially of the respiratory (nose, throat, or lungs) or gastrointestinal (stomach or intestines) tract. This suggests infections may trigger IgAN or make it worse.

When you get sick, your body makes more IgA to fight germs. In people with IgAN, this response may be overactive. Colds, flu, or tonsillitis — and changes in gut bacteria — can trigger flare-ups or worsen symptoms.

This doesn’t mean infections cause IgAN. Instead, they may trigger symptoms or make an underlying immune problem worse.

4. Other Health Conditions

Some health conditions seem to increase the risk of developing IgAN or make it worse. These include:

• Liver disease — When the liver is damaged, it may not clear IgA from the blood properly, leading to higher levels that can build up in the kidneys.
• Celiac disease — People with celiac disease, a condition triggered by gluten, may have higher IgA levels and a greater risk of kidney inflammation.
• Inflammatory bowel disease (IBD) — Conditions like Crohn’s disease and ulcerative colitis also affect the immune system and gut, where much of the body’s IgA is made.

Researchers continue to study how these diseases may be connected to IgAN. These conditions may lead to abnormal IgA or increase the risk of kidney damage.

5. Environmental and Lifestyle Factors

While genes and the immune system play key roles, environmental and lifestyle factors may also affect risk and how severe the disease becomes. These include:

• Smoking — Smoking can worsen kidney damage and raise blood pressure, both of which make IgAN progress faster.
• High blood pressure — Long-term high blood pressure adds stress to the kidneys and can speed up loss of kidney function.
• Medications — Rarely, some cancer or immune medications (such as immune checkpoint inhibitors or tumor necrosis factor-alpha inhibitors) may be linked to IgAN.
• Diet and lifestyle — Diets high in salt may worsen blood pressure issues, which affect overall kidney health.

These factors don’t cause IgAN directly, but they can make it harder for the kidneys to stay healthy once the condition develops.

6. Gender and Ethnicity

According to Mayo Clinic, IgAN can affect anyone, but it appears more often in men than women and is more common among white and Asian people than it is in Black people. So far, researchers have only observed these differences and don’t yet know the exact reason why risk varies by gender and ethnicity.

7. Unknown Triggers

Although scientists have identified many risk factors, the exact cause of IgAN is still not fully understood. It may take a combination of genetic, immune, environmental, and lifestyle factors coming together at the right time for the disease to begin.

This means that although you can’t always prevent IgAN, you can take steps to protect your kidneys once you know you have it. Regular checkups, blood pressure control, not smoking, and following your doctor’s advice about medications and diet can all help slow disease progression.

Living With IgA Nephropathy

If you or someone you love has IgAN, it’s natural to feel uncertain or worried about the future. Remember that everyone’s experience is different. Some people live for many years with mild symptoms, while others may need more regular monitoring or treatment.

Working closely with your nephrologist (kidney specialist), staying on top of lab tests, and making healthy lifestyle choices can make a big difference. Managing blood pressure, avoiding medications that can harm the kidneys, and eating a balanced, low-salt diet are all helpful steps.

Join the Conversation

On myIgANteam, people share their experiences with IgA nephropathy, get advice, and find support from others who understand.

What has helped you the most in managing your kidney health? Let others know in the comments below.