What is Focal Segmental Glomerulosclerosis (FSGS)?

One of the scariest things that you can hear a loved one say is “I’m getting a biopsy.” Individuals only get a biopsy when there is a suspicion that there is something wrong that could be causing disease in an individual. Biopsies are also fairly invasive as they always involve removing tissue from the one being biopsied, and then there is always what feels like a never-ending waiting period as you await the return of results from the biopsy; however biopsies are a useful tool that permits providers to give patients a diagnosis of an individual condition.

One medical field that commonly uses biopsies is that of nephrology. Kidney biopsies allow providers to give a definitive diagnosis of symptoms that a patient may have. In fact, in patients who present with various symptoms that are associated with kidney abnormalities (such as decreased blood protein, protein in the urine, and swelling of the body), a kidney biopsy can help to identify the exact cause of the condition.

If a patient consistently has protein in the urine, a provider may suspect that the patient has Focal Segmental Glomerulosclerosis (FSGS), a condition that arises due to scarring and damage of the glomeruli of the kidney. The glomeruli are responsible for filtering the blood to ensure the blood is clean of toxins, and that products that need to be retained in the blood are retained. If a patient has FSGS, they can end up losing quite a bit of the protein in their blood and experience decreased blood protein and a corresponding increase in protein in the uring, alterations in fat and cholesterol levels of the blood, and systemic swelling, including in their limbs.

Over time, this condition can cause further worsening of the condition in the kidneys and result in development of end-stage renal disease (ESRD). Patients who reach ESRD usually end up requiring treatment with dialysis and an eventual kidney transplant.

When a provider performs a kidney biopsy of a patient, their sample will be examined to determine if a patient has FSGS; however, it is often also useful to determine if the patient may have a genetic factor that alters their risk of developing FSGS. For example, patients who have a homozygous (on both alleles) mutation in the APOL1 gene are known to have an increased risk of developing FSGS. In fact, this gene is such a big player in the health of kidneys, that it is know that even a donated kidney that has both APOL1 risk alleles present can lead to increased risk of failure of the transplanted kidney. This is why it is so important to consider testing for FSGS-associated genes when a patient is exhibiting symptoms of FSGS.

Additionally, alterations in genes associated with FSGS can vary based on a patient’s individual demographics. For example, alterations in APOL1 are known to be more frequent in patients with African ancestry. The presence of alterations in APOL1 are not sufficient to cause disease, however they are known to increase the overall risk.

When a patient has an alteration in APOL1, it is important to closely monitor the patient to ensure that they don’t develop overall symptoms of FSGS. It is also important to consider whether they would benefit from familial genetic testing and counseling in order to ensure that additional family members don’t suffer from untreated FSGS.

While there aren’t currently very many therapeutic treatments available for individuals with FSGS, there are a number of treatments currently being examined in clinical trials. In fact, patients who have obtained a genetic diagnosis for FSGS are often resistant to steroid treatment and additional treatment options commonly used for chronic kidney disease.