Your immune system produces the antibody Immunoglobulin A (IgA) to help fight off viruses and bacteria. Sometimes, though, these antibodies can form deposits that build up in the kidneys, cause inflammation, and harm your kidney tissue. When this occurs, the condition is called Immunoglobulin A nephropathy (IgAN), also known as Berger’s disease.

What causes IgAN?

Experts think that IgAN is an autoimmune disease, which is when cells that are designed to protect your body start attacking it instead. People who have IgAN have a higher level of Immunoglobulin A (IgA) in their blood, which contains less of a type of sugar, called galactose. 

The normal antibodies target the galactose-deficient antibodies as foreign; they respond by attaching to them in an attempt to neutralize them. The clumps that form when this occurs can get stuck in your kidneys’ filtering mechanism. 

There may also be a genetic component to the disease’s development. 

How does IgAN harm my kidneys?

The structural and functional unit of your kidneys’ filtering system is called a nephron. Inside the nephron are glomeruli, or clusters of small, looping blood vessels that filter the blood to remove wastes and excess fluid. 

When the IgA deposits build up in the glomeruli, they become weakened and inflamed, allowing blood and proteins to leak into your urine. Over time, scarring can occur in the nephron, which further damages the kidney and leads to kidney failure and dialysis.

Between 20 and 40% of adults progress to kidney failure, or end-stage kidney disease (ESKD), approximately 10 to 20 years after the onset of IgAN. 

What are the risk factors for IgAN?

IgAN is the third most common type of kidney disease, after those caused by diabetes and hypertension, and it can occur to people of all ages, sexes, and races. Scientists have identified certain factors, however, that can increase your risk. 

These risk factors include:

• Male sex
• Late teen to early 30s
• Family history of IgAN or IgA vasculitis
• Asian or Caucasian

What are some signs and symptoms of IgAN?

As with several other kidney diseases, IgAN may be asymptomatic in its early stages. Noticeable symptoms in later stages may include the following:

• Hematuria (blood in the urine): It may or may not be visible to the naked eye. If visible, your urine may look pink in color or even a tea-like brown. Hematuria may occur during or immediately following a cold or other respiratory infection.
• Albuminuria (also proteinuria): Increased levels of a protein, called albumin, in urine cause urine to foam. Albumin is the primary protein found in your blood, and your kidneys usually prevent it from leaking into your urine. A common symptom of albuminuria is edema (swelling) in your ankles, face, feet, hands, or legs.

What are some complications of IgAN?

IgAN complications may include:

• High blood pressure
• Sudden, temporary loss of kidney function
• Progressive kidney function loss that leads to kidney failure
• High cholesterol
• Cardiovascular problems
• Henoch-Schönlein purpura

How is IgAN diagnosed?

Most forms of kidney disease can generally be diagnosed with blood and urine tests, but an IgAN diagnosis requires a kidney biopsy. This type of biopsy is guided by an ultrasound or CAT scan, during which a small tissue sample is extracted from your kidney for further examination. The procedure may take place in a hospital or outpatient center. Like blood and urine tests, the biopsy is also able to indicate the degree of kidney function loss.

What treatment options are there for IgAN?

There is currently no cure for IgAN. Treatment is geared toward slowing the progression of the disease and delaying, or preventing, kidney failure. 

The most common treatment methods include:

Medications to:

• Control blood pressure (ACE inhibitors, ARBs, beta blockers)
• Lower cholesterol (statins)
• Boost the immune system (corticosteroids, cyclophosphamide)
• Remove excess fluid from the blood (diuretics)

Lifestyle changes, such as:

• Limiting dietary sodium 
• Decreasing liquid intake
• Avoiding saturated fat and cholesterol
• Limiting protein
• Taking dietary supplements, such as fish oil

Avoid making major changes on your own. Your doctor and dietician will help you craft a personalized diet plan to maximize safety and nutrition.

For more information, visit the IgA Nephropathy Foundation and National Kidney Foundation websites.

*National Institute of Diabetes and Digestive and Kidney Diseases. (2020, Nov. 9). IgA Nephropathy. https://www.niddk.nih.gov/health-information/kidney-disease/iga-nephropathy