Understanding Genetics and Keratoconus
If the last time you learned about genetics was in biology class, you’re not alone. To best understand genetic testing it’s important to revisit the basics.
There are two main categories of genetic diseases: Monogenic and Polygenic.
Monogenic = If you have the gene, you have the disease. The results are presented as a Yes or No. Lattice Corneal Dystrophy is a Monogenic Disease.
Monogenic diseases are associated with a single gene, testing is straightforward: you either have the defective gene or you don’t. It’s a “positive” or “negative” answer. Examples of monogenic diseases include Huntington’s disease and cystic fibrosis.
Polygenic = If you have more genes associated with the disease, you have a higher genetic risk of the disease. The results are presented as a risk score. Keratoconus is a Polygenic Disease
Polygenic diseases are associated with several or lots of genetic variances. These genetic factors interact with environmental factors to cause the disease. Keratoconus is a polygenic disease. Other examples of polygenic diseases include hypertension and diabetes.
Why have a genetic test for keratoconus?
Genetic tests help to guide personalized, precision, medicine. If a patient is identified with a high genetic risk for keratoconus, then your doctor will prescribe more frequent follow-up, recommend avoiding or treating environmental factors, such as treating ocular allergies and stopping eye rubbing, and may initiation early intervention with treatments such as crosslinking. These treatments if initiated at the earliest onset of the disease can slow the trajectory of the disease, preventing advanced disease.
How is risk for keratoconus calculated?
Risk calculation in polygenic diseases such as keratoconus is complex. Researchers have identified 75 genes associated with keratoconus, discoveries that enabled Avellino to develop the AvaGen Genetic Eye Test, which screens for thousands of variants on those 75 genes and provides a risk assessment based on those findings.
AvaGen Genetic Eye Test is a major breakthrough in understanding a patient’s risk of keratoconus. It provides risk scores for both symptomatic and asymptomatic keratoconus patients.
The results are presented as a simple score, 0 to 100, which breaks down into low, moderate, or high risk.
Is keratoconus genetic or enviromental?
Both genetic and environmental factors contribute to the development of keratoconus. An example of environmental factors impacting the development of keratoconus is eye rubbing. Does this mean all people that rub their eyes will develop keratoconus? No, and this is where genetics play a role. For a person with high genetic risk, eye rubbing compounds and increases the risk for keratoconus development.
How is the genetic data collected?
The test is simple. It is performed in-office with a cheek swab, also known as a buccal swab, which collects a small number of cells from the inner cheek.
Who should get genetic testing for keratoconus?
Patients with a diagnosis of keratoconus should consider having their family members, especially their children, tested.