NephCure Specialist, Dr. Rasheed Gbadegesin, MD, MBBS, responds to our questions regarding genetic testing. Dr. Gbadegesin is a pediatric nephrologist at Duke University Medical Center. He is also a professor of pediatrics and professor in medicine, focusing his studies on molecular genetics of glomerular disease and genetic risk factors for childhood onset idiopathic Nephrotic Syndrome.
“Why should I seek genetic testing?
Nephrotic Syndrome and other rare kidney diseases are common causes of human suffering in the United States and all over the world. Nephrotic Syndrome is seen in all age groups, but it is more common in children. Nephrotic Syndrome is divided into steroid sensitive nephrotic syndrome (SSNS) and steroid resistant nephrotic syndrome (SRNS) based on response to steroid treatment. Most patients with SSNS will have excellent outcomes, while those with SRNS who are also unresponsive to other treatments may develop progressive kidney damage that will ultimately require dialysis and kidney transplantation.
The cause of Nephrotic Syndrome and other kidney diseases is unknown in majority of cases. However, with the mapping of the Human Genetic Code and the development of tools to read the codes, we are now learning more about the potential causes of Nephrotic Syndrome and other kidney diseases.
Using Nephrotic Syndrome as an example, we now know that a significant proportion of SRNS type are due to defects in one of 70 genes. A study from Columbia University, and other studies from the US, Canada, and Europe, showed that up to 10% of kidney disease patients with kidney disease of unknown cause have defects in one of these 70 genes and other kidney diseases genes. In addition, some genetic factors have been associated with high risk of developing kidney disease, a very good example is the association between variants in the APOL1 gene and high risk of kidney diseases in people of African ancestry.
These findings are very exciting and will most likely lead to early and accurate diagnosis of different kidney diseases. They may also facilitate the identification of other diseases that may be associated with genetic kidney diseases, for example, hearing loss in people with defects in COL4A5 genes and early onset diabetes in patients with HNF1B gene defects.
“Who should seek genetic testing? When in my journey is it appropriate to do so?”
The simple answer is that genetic testing should be offered to those who are suspected of having genetic kidney disease, and testing should be done as soon as the diagnosis is made. For example, patients with steroid resistant nephrotic syndrome (SRNS), especially if it is associated with a history of kidney diseases in other family members, should undergo appropriate genetic testing without any delay. This approach is very important because early diagnosis of genetic SRNS will facilitate 1) tailored use of medications to reduce side effects and toxicity, 2) use of appropriate medications that are directed towards the specific genetic defect, 3) precise discussion with patients and family members on what to expect short and long term, 4) putting in place measures to prevent or slow rate of kidney damage, and 5) safe planning and timing of kidney transplantation if needed.
In conclusion, genetic testing should be widely available to patients with suspected genetic kidney disease. The genetic data should be discussed with family members and experts in genetic kidney disease for accurate interpretation of results. The information from the genetic testing should be studied carefully to improve the short- and long-term outcome for the patient and other family members.
If you would like to learn more about genetic testing, talk to your nephrologist and ask about the steps necessary to obtain approval from your insurance. It is important to also seek genetic counseling once the genetic testing comes back. If you are having trouble getting genetic testing approved through your insurance or your doctor is not keen on obtaining these tests, click here to learn more about obtaining your genetic testing for free through various studies or organizations.