May 14, 2019
Depending on when you or your loved one were originally diagnosed, you may have been told you had membranoproliferative glomerulonephritis (MPGN), and the type I, II, or III. But in 2013, with a better understanding of the condition, some cases were reclassified as C3 glomerulopathy or C3G. When this happened, your original diagnosis may have changed.
How a Diagnosis Is Made
Various conditions, such as diabetes, infections, autoimmune diseases, and cancer affect the health of 1 or both kidneys. For many conditions, it is important for doctors to see inside the kidney to better understand what may be causing the problem. A biopsy is a medical procedure in which a tissue sample is removed from the kidney for examination under a microscope. When magnified to a high degree, a tissue sample looks like a road map to the well-trained eye. Specialists known as pathologists examine the road map to identify the location and type of damage or "pattern of injury" to help determine a disease diagnosis.
MPGN is a condition affecting the kidneys in which the immune system is not working normally. The immune system, which is normally responsible for protecting the body against infections, begins to attack the small, blood filtering units inside the kidneys, or glomeruli. The condition is diagnosed by finding a distinct pattern of injury in a tissue sample where pieces from the immune system or "deposits" are visible. In the past, doctors referred to an MPGN diagnosis as either type I, II, or III based on where the damage and deposits were found in the kidney. But even once the type was determined, the specific cause of the damage was often still in question.
New Ways to Classify
When doctors and experts created the new classification to identify C3G as its own disease, the change was made in order to reflect an improved understanding that different parts of the immune system may be involved in different MPGN patients.
In C3G, experts believe that a specific part of the immune system, the alternative pathway of the complement system, is not well controlled, often resulting in damage to the kidneys.
By finding mostly deposits of the complement system protein C3 in the small filters of the kidney during a biopsy, it indicates that the alternative pathway is overactive and helps doctors to confirm a diagnosis of C3G.
Reclassifying the 3 Types of MPGN
Based on this new disease criteria, some patients previously diagnosed with a type of MPGN may actually have C3G:
For MPGN patients that do not meet the criteria for C3G, experts believe that other parts of the immune system may be contributing to their kidney damage.
While it can be confusing, the new reclassification means researchers are getting closer to understanding why and how the kidneys are damaged. Each additional discovery and piece of evidence may help facilitate new treatments and therapies.
If your diagnosis has changed or if you're still trying to get a better understanding of C3G and how it affects your kidneys, we encourage you to talk to your doctor. Together you can work with him or her to get a better understanding of your specific condition and what you can do to effectively manage symptoms.
Thank you for visiting WeC3GTM
You are now leaving the WeC3G.com website and being directed to a third-party website. Achillion Pharmaceuticals, Inc. is not responsible for the content of the site you are about to visit.
Would you like to continue?
Continued use of this site indicates you have accepted this policy.