There are two types of FSGS:

Primary or idiopathic FSGS occurs without a clear underlying cause. Doctors believe it may be related to factors in the blood that damage the kidney filters. This may be linked to a fault in the immune system, which is the body’s way of protecting itself from infection.

Secondary FSGS occurs because of other factors such as:

  • Other medical conditions
  • Medications
  • Having reduced kidney tissue
  • Long-term high blood pressure
  • Infections

Some cases of FSGS are due to a genetic mutation that affects the structure of part of the glomerulus in the kidney, which causes the protein leak. Your child’s doctor will talk to you about this and may arrange for a genetic test to be done to see if other family members are affected, but this is very rare.

More information

  • About the urinary system and kidneys

    If your child has a health condition that affects their kidneys or another part of the urinary system, you may wish to find out more.

  • Focal segmental glomerulosclerosis (FSGS)

    FSGS and IgM nephropathy cause nephrotic syndrome in children, where the kidneys leak too much protein into the urine and lead to swelling in the body.

  • Urine tests

    Your child may have urine tests at the clinic or hospital to help diagnose a condition or find out how well a treatment is working.