Genetic Testing Guide for IRDs

Targeted Gene Panel

Whole Exome Sequencing (WES)

Whole Genome Sequencing (WGS)

Entire genome (coding + non-coding)

Single Gene Testing

Blueprint Genetics

GeneDx

Invitae

Prevention Genetics (Exact Sciences)

Molecular Vision Laboratory

SPARK (Foundation Fighting Blindness)

Strong scientific evidence that this variant causes the condition. Multiple affected families, functional studies, and/or well-established mechanism.

Probably disease-causing (>90% certainty)

Strong evidence supporting pathogenicity but not yet definitive. May have limited functional data or fewer reported cases.

Insufficient evidence to classify as pathogenic or benign. May be reclassified as more data accumulates. Common in less-studied genes or populations.

Probably not disease-causing (>90% certainty)

Evidence suggests this variant does not cause disease. May be common in population databases or have no predicted functional impact.

Definitively not disease-causing

Strong evidence that this variant is a normal population variant with no disease association. Common in healthy individuals.

My Retina Tracker / SPARK

Free genetic testing through a research registry. Results are returned clinically. Largest IRD patient registry in the US.

Open Access Genetic Testing

Sponsored testing programs that cover the cost of genetic testing for qualifying patients. Check availability periodically.

No-Cost Genetic Testing for Rare Disease

Patient assistance programs and sponsored testing initiatives for qualifying individuals.

Undiagnosed Diseases Program

NIH research program for patients who remain undiagnosed. Comprehensive genomic analysis at no cost to the patient.

Genetic Testing Guide

Complete guide to genetic testing for inherited retinal diseases. Learn about test types, how to get tested, and interpreting results.

A comprehensive guide to genetic testing for inherited retinal diseases — why it matters, what tests are available, how to get tested, and how to understand your results. Knowing your genetic diagnosis is the first step toward accessing emerging therapies.

Why Genetic Testing Matters

For patients with inherited retinal diseases, genetic testing is not just diagnostic — it is the gateway to treatment. With over 40 gene therapies and other targeted treatments in clinical trials, knowing your specific genetic mutation determines which therapies you may be eligible for.

Clinical Trial Eligibility

Most IRD clinical trials require a confirmed genetic diagnosis. Without knowing your mutation, you cannot enroll in gene-specific therapies like Luxturna (RPE65), AGTC-501 (CNGB3), or EDIT-101 (CEP290). A genetic diagnosis opens doors to treatments that may preserve or restore vision.

Family Planning & Cascade Testing

Understanding the inheritance pattern (autosomal recessive, dominant, or X-linked) helps families assess risk for future children and identify at-risk relatives who may benefit from early monitoring or preventive measures before symptoms appear.

Prognosis & Management

Different mutations in the same gene can cause different rates of progression. Knowing the exact variant helps predict disease course, guides monitoring frequency, identifies systemic associations (e.g., Usher syndrome = hearing loss + RP), and informs low-vision rehabilitation planning.

The Window of Opportunity

Gene therapies work best when delivered before significant cell loss. Getting tested early — even if no treatment is available today — means you will be ready when a therapy for your specific gene enters clinical trials. The average time from trial announcement to enrollment is only 3–6 months, and many trials fill quickly. Having your genetic diagnosis ready ensures you don't miss your window.

Types of Genetic Tests

Several types of genetic testing are available, each with different scope, cost, and turnaround time. The right choice depends on your clinical presentation, family history, and whether previous testing has been performed.

Advantages

Limitations

Recommended Testing Pathway

Most patients (~60-70%) receive a diagnosis from the initial panel test. Of those remaining, WES resolves another 10-15%. WGS can identify deep intronic variants and structural rearrangements missed by other methods.

Recommended IRD Testing Labs

Several clinical laboratories specialize in inherited retinal disease genetic testing. These labs maintain comprehensive panels covering 280–350+ known IRD genes and employ retinal genetics specialists for variant interpretation.

Panel:

Choosing a Lab

When selecting a testing lab, consider: (1) panel size and whether it covers genes relevant to your clinical presentation, (2) whether the lab has retinal genetics expertise for variant interpretation, (3) insurance acceptance and out-of-pocket costs, (4) turnaround time, and (5) whether they offer reflex testing (automatic escalation to WES if the panel is negative). Your retinal specialist or genetic counselor can help recommend the most appropriate lab.

The Testing Process

Genetic testing for IRDs follows a structured process from initial consultation through results delivery. Understanding each step helps you prepare and set appropriate expectations.

Clinical Evaluation & Referral

Your retinal specialist (ophthalmologist or optometrist specializing in retinal disease) evaluates your symptoms, family history, and clinical findings (OCT, ERG, visual fields). Based on the clinical picture, they determine whether genetic testing is appropriate and which test to order.

Genetic Counseling (Pre-Test)

A genetic counselor explains what testing can and cannot reveal, discusses possible outcomes (including uncertain results), reviews inheritance patterns, and obtains informed consent. This session helps set expectations and prepares you for any result.

Sample Collection

A blood draw (preferred) or saliva sample is collected. Blood provides higher-quality DNA and is recommended when possible. The sample is sent to the chosen laboratory with the test order and relevant clinical information.

Laboratory Analysis

The lab extracts DNA, sequences the relevant genes, and runs bioinformatic pipelines to identify variants. Each variant is classified according to ACMG/AMP guidelines. A retinal genetics specialist reviews findings in the context of the clinical phenotype.

Results & Genetic Counseling (Post-Test)

Results are returned to the ordering clinician and discussed with you, ideally with a genetic counselor present. The report explains which variants were found, their classification, and clinical significance. Next steps are outlined based on the findings.

Insurance & Cost Considerations

Often Covered

Panel testing ordered by a specialist with documented clinical findings

Testing with prior authorization from insurance

Cascade testing for at-risk family members (known familial variant)

Medicare/Medicaid coverage for diagnostic genetic testing

Tips to Reduce Costs

Ask your lab about patient assistance programs (many offer $0 or reduced-cost options)

Check if you qualify for sponsored research testing (FFB SPARK, Invitae programs)

Request a cost estimate and prior authorization before testing

GINA protects against genetic discrimination in health insurance and employment

How to Interpret Your Results

Genetic test results classify each identified variant according to the ACMG/AMP (American College of Medical Genetics) five-tier system. Understanding these classifications is essential for knowing what your results mean and what actions to take.

What This Means For You

Key Terms in Your Report

Homozygous

Both copies of the gene carry the same variant. Common in autosomal recessive conditions when parents are related (consanguinity) or from the same genetic background.

Compound Heterozygous

Two different pathogenic variants in the same gene, one inherited from each parent. The most common finding in autosomal recessive IRDs.

Heterozygous

One copy of the gene has a variant. Sufficient to cause disease in autosomal dominant conditions; carrier status in recessive conditions.

Hemizygous

One variant on the X chromosome in males (who have only one X). Relevant for X-linked conditions like RPGR-associated RP and choroideremia.

De Novo

A new mutation not inherited from either parent. Occurs spontaneously. Important for recurrence risk counseling — siblings are typically not at increased risk.

Incomplete Penetrance

Not everyone with the variant develops the condition. Some family members may carry the variant without symptoms. Common in some dominant IRDs.

What If Your Results Are Negative?

A negative result does not rule out a genetic cause. Approximately 30-40% of IRD patients do not receive a molecular diagnosis on initial panel testing. Possible reasons include: (1) the causative gene is not on the panel, (2) the variant is in a non-coding region not covered by the test, (3) the variant is a structural rearrangement not detectable by sequencing, or (4) the condition has a novel genetic cause not yet described. Next steps include escalating to WES or WGS, enrolling in research studies, or re-analyzing data periodically as new genes are discovered.

What to Do After Getting Results

Once you have your genetic test results, several important next steps can help you make the most of this information for your care, your family, and your future treatment options.

Genetic Counseling Follow-Up

Meet with a genetic counselor to fully understand your results, discuss inheritance patterns, assess risk to family members, and explore reproductive options (preimplantation genetic testing, carrier screening for partners). A counselor can also help you process the emotional impact of a genetic diagnosis.

Check Clinical Trial Eligibility

Search for active clinical trials targeting your specific gene on ClinicalTrials.gov and our Treatment Pipeline. Register with the My Retina Tracker registry to be notified when new trials open for your gene.

Family Cascade Testing

Once a pathogenic variant is identified, at-risk family members can be tested for that specific variant (much faster and cheaper than full panel testing). This identifies carriers, presymptomatic individuals who may benefit from early monitoring, and family members who can be reassured they don't carry the variant.

Connect with Patient Communities

Join condition-specific or gene-specific patient communities and registries. Organizations like the Foundation Fighting Blindness, Usher Syndrome Coalition, and condition-specific foundations connect patients with similar diagnoses, share research updates, and advocate for therapy development. Visit our Resources page for a full directory.

Free & Low-Cost Testing Programs

Cost should not be a barrier to genetic testing. Several programs offer free or reduced-cost testing for patients with inherited retinal diseases. Eligibility varies by program.

Need Help Getting Started?

If you're unsure where to begin, start by asking your retinal specialist about genetic testing. If you don't have a retinal specialist, use our Find a Specialist directory to locate an IRD expert near you. Many academic medical centers have dedicated ophthalmic genetics clinics that coordinate testing, counseling, and clinical trial referrals.

Take the Next Step

Genetic testing is the foundation for accessing emerging IRD therapies. Whether you're newly diagnosed or have lived with an IRD for years, it's never too late to get tested.

Find a Specialist

Connect with genetic counselors and retinal specialists who can order and interpret tests.

IRD Conditions Database

Explore detailed profiles of 53 inherited retinal diseases with genetics and symptoms.

Gene Index

Browse all 125 genes associated with inherited retinal diseases.