Glossary

Autoantibodies

Antibodies that mistakenly target and attack your body’s own healthy tissues, instead of fighting off infections.

C3 protein

A protein that plays a central role in the complement system. When the complement system becomes overactive, excessive breakdown of C3 results in inflammation and a buildup of C3 fragments in the kidneys.

C3G (C3 glomerulopathy)

A rare kidney disease caused by an overactive complement system, a part of your immune system that normally helps fight infections. In C3G, the complement system mistakenly attacks the kidneys, causing C3 fragments to build up. Over time, this buildup leads to inflammation and kidney damage.

Complement system

Part of the immune system made up of a network of proteins that work together to help protect the body from infections, clear out damaged cells, and promote inflammation to heal injuries.

eGFR (estimated glomerular filtration rate)

A measurement of how well the kidneys are filtering waste from the blood. It calculates this based on your blood creatinine levels, age, and gender.

Genetic testing

A blood test that involves analyzing a person’s DNA to identify changes or mutations in genes, chromosomes, or proteins.

Glomeruli

Tiny, ball-shaped structures within the kidneys that act as the primary filtering units of the blood.

Immunoglobulins

Proteins made by your immune system; they are also called “antibodies.” Their job is to help protect your body by recognizing and fighting off germs like bacteria and viruses.

Immunological testing

Evaluates the functioning of the immune system by measuring the levels and activity of immune components, such as antibodies, complement proteins, or immune cells.

Kidney biopsy

A medical procedure in which a small sample of kidney tissue is removed and examined under a microscope or other imaging tools to diagnose or monitor kidney diseases.

Primary IC-MPGN (immune-complex membranoproliferative glomerulonephritis)

A rare kidney disease caused by an overactive complement system, a part of your immune system that normally helps fight infections. In primary IC-MPGN, the complement system mistakenly attacks the kidneys, causing immunoglobulin fragments (antibody proteins) or a combination of immunoglobulin and C3 fragments to build up. Over time, this buildup leads to inflammation and kidney damage.

Proteinuria

High levels of protein in the urine, which are detected through a urine test (dipstick test and/or urinalysis).

uPCR (urine protein-to-creatinine ratio)

Measures how much protein is in your urine. High protein levels (proteinuria) can signal kidney damage.