Genetic Testing

Anyone with an inherited retinal disease (IRD), including Leber congenital amaurosis (LCA), should strongly consider genetic testing. Genetic testing often identifies the mutated gene responsible for vision loss. Armed with this important information, you and your doctor can determine the best course of action for your disease and discuss how the latest research advances might apply to you.

You won’t know if you’re a candidate for gene therapy clinical trials or any potential gene therapy treatments until you know your genetic mutation. Once you know your mutated gene, you can also participate in natural history studies or other studies that help researchers advance treatments.

Knowing the disease-causing gene also confirms the clinical diagnosis and helps you determine whether other family members are at risk of inheriting the disease. There are approximately 27 confirmed genes associated with LCA.

A note on the inheritance of LCA: Genes normally come in pairs; we have two copies of every gene in our cells. In a recessive disease, both copies of the gene pair must be mutated for the child to be affected. The vast majority of people with LCA inherit the condition through recessive inheritance.

What that means is that the affected child’s parents each have one mutated copy of the same LCA gene and one normal copy. The parents are unaffected and usually have no idea they’re carriers. Each of their children has a 1-in-4 chance of inheriting two mutated gene copies (i.e., one mutated copy from each parent) and having LCA.

How to get a genetic test: Getting genetic testing is easy. It is usually performed in a doctor’s office, where a saliva sample or swab is collected from the inside of the cheek. The sample is sent to a laboratory, and results are usually available within a few months.

Your doctor and/or a genetic counselor can explain the test results and recommend next steps.