Focal segmental glomerulosclerosis (FSGS) is a disease in which scar tissue develops on the parts of the kidneys that filter waste from the blood (glomeruli). FSGS can be caused by a variety of conditions.

FSGS is a serious condition that can lead to kidney failure, for which the only treatment options are dialysis or kidney transplant. Treatment options for FSGS depend on the type you have.

Types of FSGS include:

• Primary FSGS. Many people diagnosed with FSGS have no known cause for their condition. This is called primary (idiopathic) FSGS.
• Secondary FSGS. Several factors, such as infection, drug toxicity, diseases such as diabetes or sickle cell disease, obesity, and even other kidney diseases can cause secondary FSGS. Controlling or treating the underlying cause often halts ongoing kidney damage and might lead to improved kidney function over time.
• Genetic (also called familial) FSGS. This rare form of FSGS is caused by genetic mutations. It's suspected when several members of a family show signs of FSGS. Familial FSGS can also occur when neither parent has the disease, but each carries one copy of an abnormal gene that can be passed on to the next generation.