IgA nephropathy (IgAN), also called Berger’s disease, is a type of glomerulonephritis. Glomerulonephritis is inflammation of the glomeruli – the blood vessels in the kidneys that filter wastes and excess fluids from the blood and excrete them in the urine.
For people with IgA nephropathy, the antibody called immunoglobulin A (IgA) is abnormal causing it to accumulate in the blood. The abnormal IgA is recognized by the immune system and antibodies are formed against it resulting in immune complexes. These immune complexes are deposited in the center of the kidneys’ glomeruli causing cellular changes within the glomeruli, including inflammation and scarring. These changes damage the glomerular filtration barrier, causing blood and protein to leak into the urine. Over time, this damage to the kidneys’ filtering capability can lead to end-stage kidney disease, also called kidney failure.
Between 30-40% of people with IgA nephropathy are diagnosed with visible hematuria (blood in the urine that may make the urine look like tea or cola).1 Another 30-40% of people are diagnosed without any symptoms, when standard urine testing reveals proteinuria (protein that has leaked into the urine) and microscopic hematuria.1 The remainder are diagnosed later in life when the disease may have already progressed, with symptoms of proteinuria, high blood pressure, swelling (edema) and low levels of protein in the blood (hypoalbuminemia).1 A definitive diagnosis typically requires blood and urine tests and a kidney biopsy.
Disease progression can be slow and varies considerably among populations.2,3
Treatment aims to reduce proteinuria to less than 1 g/day and reduce blood pressure which is important for long-term preservation of kidney function.
IgA nephropathy frequently occurs in adolescence or early adulthood, usually in the second and third decades of life.1 Estimated incidence of IgA nephropathy is 2.5 per 100,000 individuals per year among adults4, with geographic, racial and ethnic variations in prevalence.1,5 Prevalence of IgA nephropathy may be higher in individuals of Pacific Asian and southern European descent versus those of North American and northern European descent.1,6 In the US, IgA nephropathy is the most common primary glomerular disease in young Caucasian adults.6 The rare kidney disease is the most common type of primary glomerulonephritis worldwide.