Originally published in NKCF Update (March 2020)
The role of genetics has been of interest among researchers and physicians as one of the factors that impact keratoconus (KC). Recent publications indicate genetic variants as well as membership in certain ethnic groups can influence who is likely to develop KC and experience disease progression.
Individuals with a family history of KC have an increased risk of developing KC. Children can be born to parents who carry an affected gene but show no symptoms with the disease. These children can either be unaffected or carry the gene mutation and have no evidence of KC (carrier) or can be diagnosed with KC (affected). At this time, the majority of individuals with KC have no known family history of the disease. As genetic testing becomes more sophisticated, scientists may identify additional gene mutations that are potential links to the disease and will provide an answer to the questions, “What causes KC?”
To identify individuals at an increased risk due to known genetic factors, Avellino Precision Medicine of Menlo Park, CA has developed the AvaGen test, the first commercially available genetic test that will help detect genetic mutations known to cause certain corneal dystrophies including keratoconus. The AvaGen test uses a non-invasive cheek swab to collect cells and then sequences the DNA. It focuses on mutations in 75 genes known known to impact corneal eye health, including the TGFBI gene that is linked to KC.
AvaGen test results will show if you carry any of the variants linked to KC and will provide a risk score. Your doctor or a genetic counselor can explain what this means to you and close family members.
Dr. John Gelles, OD, of the Center for Keratoconus at the Cornea and Laser Eye Institute (CLEI) in Teaneck, New Jersey warns that genetic testing cannot take the place of regular exams and patient monitoring, “With the availability of new methods to treat keratoconus, early diagnosis has become ever more important. Tests like this give us a valuable new tool for KC diagnosis. However, such a test will not obviate the necessity of careful and regular clinical screening of at-risk patients, including relatives of KC patients, younger patients whose vision cannot be corrected fully with spectacles, and those with irregular astigmatism to name a few.”
The objective of the AvaGen test is to help physicians create individualized treatment plans for their patients and help patients make informed decisions about their healthcare. Dr. Steven Greenstein, MD, also of the CLEI Center for Keratoconus noted, “Although the concept of being able to diagnosis a disease prior to clinical manifestations is ideal, prophylactic treatment such as corneal crosslinking would not likely be performed without clinical evidence of disease. Nonetheless, testing like this will be valuable both in the clinic and for KC research in the future.”
To learn more about the AvaGen test, visit www.avellino.com/en/products/avagen-test/ . The test must be ordered by your doctor and is currently not covered by insurance. Ask your eye doctor if you believe you could benefit from this test.
Dr. Steven Greenstein, MD is a fellowship-trained cornea specialist working at the Center for Keratoconus at the Cornea and Laser Eye Institute in Teaneck, New Jersey.
Dr. John Gelles, OD, FCLSA, FSLS, is a member of the Hersh Vision Group’s Cornea and Laser Eye Institute. He is a board member of the International Keratoconus Academy and a fellow of the Contact Lens Society of America and the Scleral Lens Education Society.