Immunoglobulin A (IgA) Nephropathy
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IgA nephropathy is a chronic kidney disease that may progress over a period of 10 to 20 years, and can lead to end-stage renal disease. It is caused by deposits of the protein immunoglobulin A (IgA) inside the glomeruli (filters) within the kidney. These glomeruli normally filter waste and excess water from the blood and send them to the bladder as urine. However, the IgA protein prevents this filtering process. This may lead to the following:
- blood and protein in the urine
- swelling in the hands and feet
The IgA protein is a normal part of the body's immune system. It is unknown what causes IgA deposits in the glomeruli; however, in more than 10 percent of affected families, IgA nephropathy is inherited by an autosomal dominant gene. Autosomal dominant inheritance means that the gene is located on one of the autosomes (chromosome pairs 1 through 22). This means that males and females are equally affected, and "dominant" means that only one gene is necessary to have the trait. When a parent has a dominant trait, there is a 50 percent chance that any child they have will also inherit the trait.
IgA nephropathy is a very heterogeneous condition, which means that the presentation varies greatly between individuals and families. In fact, some persons who inherit the gene may not have any symptoms, but could pass the gene on to the next generation. Many times men are affected more often than women.
IgA nephropathy is a silent disease that may go undetected for years, but usually onsets before the age of 40. The most common symptom is blood in the urine. It takes many years to progress to the stage where it causes detectable complications such as swelling, recurrent upper respiratory infections, or intestinal disease.
In addition to a complete medical history and physical examination, diagnostic procedures for IgA nephropathy may include the following:
- measurement of blood pressure
- measurement of blood cholesterol levels
- measurement of protein levels in the urine
- measurement of protein levels in the blood
- kidney biopsy (to identify IgA deposits) a procedure in which tissue samples are removed (with a needle or during surgery) from the kidney for examination under a microscope; to determine if cancer or other abnormal cells are present.
Specific treatment for IgA nephropathy will be determined by your physician based on:
- your age, overall health, and medical history
- extent of the disease
- your tolerance for specific medications, procedures, or therapies
- expectations for the course of the disease
- your opinion or preference
Treatment may include:
- diet modification
- cholesterol reduction
- cessation of smoking
- exercise and maintenance of normal body weight
- high fluid intake
- blood pressure control
Treatment focuses on slowing the progression of the disease and preventing complications, such as high blood pressure, which further damages the glomeruli. Researchers funded by the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) are conducting studies to understand how the IgA deposits are formed and whether dietary supplements such as fish oil or medications such as prednisone can inhibit kidney inflammation and scarring.
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Online Resources of Kidney and Urinary Disorders