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Not classic autoantibodies
Involves galactose-deficient IgA1 and autoantibodies against it, forming damaging immune complexes
IgA nephropathy is a chronic autoimmune kidney disease where a protein called immunoglobulin A (IgA) builds up in the kidneys’ filtering units (glomeruli). This buildup causes inflammation and damage, slowly impairing the kidneys’ ability to filter waste and excess fluid from the body.
Early stages often have no symptoms. When symptoms do appear, they may include:
Blood in urine (hematuria) – either visible or microscopic
Foamy urine – from excess protein
Swelling – especially in the feet, hands, or face
High blood pressure
Fatigue
Lower back or flank pain
Often triggered or worsened by respiratory or gastrointestinal infections.
IgA nephropathy is believed to be caused by a faulty immune response involving abnormal IgA1, a type of antibody. This form of IgA is missing certain sugars (galactose-deficient IgA1), making it look “foreign” to the immune system. The body attacks it, forming clumps (immune complexes) that get stuck in the kidneys and cause inflammation.
Key contributors include:
Genetics – family history increases risk
Immune system abnormalities – production of galactose-deficient IgA1
Infections – particularly respiratory or GI tract infections can trigger flare-ups
Environmental factors – unclear, but may play a role
Autoimmune factors – not always classic autoimmunity, but involves auto-reactive processes
Diagnosis typically involves:
Urinalysis – shows blood and protein in urine
Blood tests – check kidney function (creatinine, estimated GFR)
Kidney biopsy – confirms IgA deposits in glomeruli
Imaging – may rule out other kidney problems
Because symptoms can be subtle, diagnosis often happens after an unrelated urine test.
There’s no cure, but treatments aim to slow disease progression and protect kidney function:
Blood pressure medications (ACE inhibitors or ARBs)
Corticosteroids or immunosuppressants (for high-risk patients)
Fish oil supplements (may reduce inflammation)
Low-salt, kidney-friendly diet
SGLT2 inhibitors (newer option in some patients)
Kidney transplant – for end-stage kidney disease
IgA nephropathy progresses slowly in most people. About 1 in 4–5 will develop kidney failure over 20 years. Others live with stable or mild disease for decades.
Controlling blood pressure and protein levels in urine are key to improving long-term outcomes.
Affects ~2 per 100,000 people per year
More common in men and young adults (teens to 30s)
Higher rates in East Asian and Caucasian populations
Wyatt RJ, Julian BA. IgA nephropathy. N Engl J Med. 2013;368(25):2402-14. doi:10.1056/NEJMra1206793
Kiryluk K, Novak J. The genetics and immunobiology of IgA nephropathy. J Clin Invest. 2014;124(6):2325-32.
KDIGO 2021 Clinical Practice Guideline for the Management of Glomerular Diseases. Kidney Int. 2021;100(4S):S1-S276.
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