NORD gratefully acknowledges Lawrence Slapcoff, MD, CM Candidate, McGill University School of Medicine, and Daniel C. Cattran, MD, Division of Nephrology, Department of Medicine, University Health Network, University of Toronto, for assistance in the preparation of this report.
IgA nephropathy is a kidney disease in which IgA, a protein meant to defend the body against foreign invaders, accumulates in the kidneys and damages them. This impairs their filtering function. As a result, the kidneys begin to let substances such as blood and protein leak into the urine. 2
This condition most often occurs in Caucasian and Asian males. It usually appears when people are in their teens to late 30s but can occur at any age.5 Many cases resolve over time.6 However, in a subset of patients, the disease may not resolve and thus can lead to end-stage renal disease (ESRD) after 20-25 years.7. Rarely the condition can progress much more rapidly leading to renal failure within a few years, if not treated.
People who have this condition most often present with one or recurrent episodes of having blood in their urine (visible hematuria). These episodes usually occur during or right after an upper respiratory tract infection such as a cold, sore throat or a gastrointestinal infection. 3,4
Treatment includes drugs that aim to slow progression of the disease and others that aim to reduce inflammation. The choice of treatment is made based on a variety of factors including blood pressure, the amount of protein in the urine and the estimated kidney function.7
The kidneys are two fist sized organs located in the back under the rib cage that serve as a filter for blood. They remove excess fluid and waste as urine, while reabsorbing the proper amount of water and other chemicals that the body needs to function.1 The name IgA nephropathy comes from the fact that that the protein depositing in the kidney has the characteristics of a normal circulating immunoglobulin protein designated IgA. In the disease, the normal protein is changed somewhat causing it to deposit in the filters of the kidney and it to leak blood and or protein. It is also named Berger’s disease as it was first described by Berger and Hinglais in 1968.2
Patients with IgA nephropathy often present with3,8:
When these symptoms are present during or directly after a respiratory infection such as a sore throat or a cold, there is a higher likelihood that the person has IgA nephropathy.3
Some patients who have either the rapidly progressive type of IgA nephropathy or chronic asymptomatic disease may present with symptoms of end-stage renal disease (ESRD) 9:
As mentioned above (“see introduction”), the kidneys serve as filters for your blood. Each kidney consists of about 1 million “mini-filters” called nephrons.
Each nephron consists of a Bowman’s capsule and tubules. The Bowman’s capsule contains many important structures such as the glomerulus, which is a series of tiny blood vessels where the initial filtration takes place. Once the fluid has been filtered by the glomerulus, it travels along the tubules, where chemicals and water are either added or removed from the filtered fluid based on the body’s needs. Once the fluid has passed through the tubules, it leaves the body as urine.1,8
For an unknown reason, patients with IgA nephropathy create abnormal IgA proteins that the body recognizes as foreign. As a result, the body attacks them, which leads to the formation of clusters of proteins called immune complexes. These immune complexes are what deposit in the kidneys and causes damage. Due to this phenomenon, IgA nephropathy can be considered an autoimmune disease. 4
The IgA protein immune complexes specifically deposit in the central area of the glomerulus in the mesangial area.4 Once these immune complexes deposit, the glomerulus (filter) become inflamed and damaged. As a result, their filtering function is damaged allowing substances such as red blood cells and proteins to pass through the damaged filter into the urine.9
When patients have respiratory infections such as a cough or sore throat, IgA immune complexes are higher in circulation4. Therefore, many of them end up depositing in the kidneys and this is when patients with IgA nephropathy typically present with symptoms such as hematuria (blood in the urine). Some patients may also experience episodes of IgA nephropathy when they have gastrointestinal infections such as the stomach flu or even after exercise.7
There is evidence to suggest that genetic factors play a role in this disease. It has been suggested that IgA nephropathy is a complex polygenic disease meaning that there are many genes and environmental factors that contribute to an individual developing the condition.10
In North America and Europe, males are two times more likely to get the disease, while in Asia, females are just as likely as males to be affected.4 In terms of ethnicity, Asians are much more likely then Caucasians who are, in turn, much more likely than black population to get IgA nephropathy. This disease most often presents between teenage years to late 30’s, but can present at any age. 5
IgA nephropathy might be suspected when a patient has bloody (red) or dark urine following a respiratory tract illness such as a sore throat or a cold.7
Although a doctor may have a high index of suspicion that their patient has IgA nephropathy based on history, physical exam, urine tests and blood tests, the only way to truly diagnose IgA nephropathy is through a kidney biopsy.4
A kidney biopsy is when a small needle is inserted into a person’s kidney in order to take a small sample of tissue. This tissue is then examined under a microscope to look for certain characteristic markers of the disease.
Clinical Testing and Work-Up
Aside from the kidney biopsy, patients should expect to have regular blood and urine tests. For patients with mild disease (normal blood pressure, low amount of protein in urine), they can expect to have tests done every 6-12 months. Patients who have more severe forms of the disease can expect more regular monitoring. 7,9
Unfortunately, there is not yet a cure for IgA nephropathy.9. However, many cases resolve on their own.6
Treatment for this condition falls under two main categories7:
Non-immunosuppressive drugs – Those aimed at preventing progression of the disease.
Immunosuppressive drugs – Those aimed at reducing inflammation.
The non-immunosuppressive drugs used are angiotensin converting enzyme inhibitors (ACE inhibitors) and angiotensin receptor blockers (ARBs). They help prevent progression of the disease through reducing the amount of protein that filters through the damaged glomerulus and enters the urine and by lowering blood pressure.
The immunosuppressive drugs used most often are corticosteroids. They reduce inflammation by limiting the inflammatory response. 9
In summary treatment for IgA nephropathy falls under two categories:
Some patients may also be prescribed a statin, which is a cholesterol lowering drug given to lower the risk of developing cardiovascular disease.
In 2021, Tarpeyo (budesonide) was approved to reduce urine protein level in adults with primary immunoglobulin A (IgA) nephropathy who are at risk of rapid disease progression.
Diet and Nutrition
Although researchers have not found that diet and nutrition play a role in causing or preventing the disease, health care providers may recommend the following dietary changes to patients who have the condition to maximize their renal health9:
Fish Oil – The efficacy of fish oil in the treatment of IgA nephropathy has not yet been determined. There have been studies showing that taking fish oil supplements may provide very modest benefits.7,11
Tonsillectomy – Studies have shown tonsillectomies, even in patients without inflamed/infected tonsils, may provide significant benefit for patients with IgA nephropathy but more research must be done.12
Information on current clinical trials is posted on the Internet at www.clinicaltrials.gov. All studies receiving U.S. government funding, and some supported by private industry, are posted on this government web site.
For information about clinical trials being conducted at the NIH Clinical Center in Bethesda, MD, contact the NIH Patient Recruitment Office:
Toll-free: (800) 411-1222
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Email: [email protected]
Some current clinical trials also are posted on the following page on the NORD website:
For information about clinical trials sponsored by private sources, in the main, contact:
For more information about clinical trials conducted in Europe, contact:
1. How Your Kidneys Work. National Kidney Foundation. https://www.kidney.org/kidneydisease/howkidneyswrk. Published 2017. Accessed July 18, 2018.
2. Salim SA. IgA Nephropathy. Medscape. https://emedicine.medscape.com/article/239927-overview. Updated February 15, 2018. Accessed July 17, 2018.
3. Cheung CK and Barratt J. Clinical presentation and diagnosis of IgA nephropathy. UpToDate. Updated Dec 19, 2017. https://www.uptodate.com/contents/clinical-presentation-and-diagnosis-of-iga-nephropathy. Accessed July 20, 2018.
4. Wyatt RJ, Julian BA. IgA nephropathy. New England Journal of Medicine. 2013;368(25):2402–2414. https://www-nejm-org./doi/full/10.1056/NEJMra1206793
5. Latif W. IgA Nephropathy. Medline. Review Date 8/1/2017. www.nlm.nih.gov/medlineplus/ency/article/000466.htm. Accessed July 19, 2018.
6. IgA Nephropathy. Renal Resource Center. Published 2012. https://kidney.org.au/cms_uploads/docs/rrc-iga-nephropathy.pdf. Accessed July 19, 2018.
7. Cattran DC and Appel GB. Treatment and prognosis of IgA nephropathy. UpToDate. Updated October 13, 2017. https://www.uptodate.com/contents/treatment-and-prognosis-of-iga-nephropathy. Accessed July 20, 2018.
8. IgA Nephropathy (Berger’s Disease). Mayo Clinic. Published August 4, 2017. https://www.mayoclinic.org/diseases-conditions/iga-nephropathy/symptoms-causes/syc-20352268. Accessed July 28, 2018.
9. IgA Nephropathy. National Institute of Diabetes and Digestive and Kidney Diseases. Published November, 2015 https://www.niddk.nih.gov/health-information/kidney-disease/iga-nephropathy. Accessed July 18, 2018.
10. Cheung CK and Barratt J. Pathogenesis of IgA nephropathy. UpToDate. Updated January 15, 2018 https://www.uptodate.com/contents/clinical-presentation-and-diagnosis-of-iga-nephropathy. Accessed July 19, 2018.
11. Reid S, Cawthon PM, Craig JC, Samuels JA, Molony DA, Strippoli GFM. Non-immunosuppressive treatment for IgA nephropathy. Cochrane Database of Systematic Reviews 2011, Issue 3. Art. No.: CD003962. DOI: 10.1002/14651858.CD003962.pub2 (cochranelibrary-wiley.com./doi/10.1002/14651858.CD003962.pub2/full)
12. Lin-lin Liu, Li-ning Wang, Yi Jiang, Li Yao, Li-ping Dong, Zi-long Li, Xiao-li Li, Tonsillectomy for IgA Nephropathy: A Meta-analysis, American Journal of Kidney Diseases, Volume 65, Issue 1, 2015, Pages 80-87,ISSN 02726386, Available from: https://doi.org/10.1053/j.ajkd.2014.06.036.(http://www.sciencedirect.com/science/article/pii/S0272638614011949)
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