Photo Credit: Orla

Some patients with inherited retinal diseases still experience multi-year diagnostic delays, but education and genetic testing have reduced this gap.

Patients with inherited retinal diseases (IRDs) “have historically had lengthy delays in being diagnosed and in accessing genetic testing,” researchers wrote in an abstract presented at the Association for Research in Vision and Ophthalmology (ARVO) annual meeting.

Although patients diagnosed with IRDs since 2018 face a significantly shorter time between presenting with symptoms, receiving a clinical diagnosis, and undergoing genetic testing than patients who were diagnosed before 2018, the “diagnostic odyssey” from symptom onset to confirmation with genetic testing is still longer than it should be, according to investigators.

The researchers conducted a retrospective review of 198 patients who made their first visit to the Shiley Eye Institute between 2020 and 2023. The study aimed to determine how the time to IRD diagnosis and genetic testing has evolved with the approval of gene therapy and improved access to genetic testing.

Physician’s Weekly (PW) spoke with study author Naomi Wagner, MS, CGC, to learn more.

PW: What prompted this research?

Wagner: In the genetics and rare disease space, we talk a lot about the diagnostic odyssey, which is the often long and sometimes quite emotional journey from symptoms to diagnosis for rare disease patients. The diagnostic odyssey for patients with rare diseases typically involves genetic testing, given that an estimated 80% of rare diseases have an underlying genetic etiology.

Historically, rare genetic diseases have been difficult to treat. We know that one hurdle to achieving a rare disease diagnosis and an accurate IRD genetic diagnosis is access to genetic testing. No-cost industry and/or advocacy-sponsored genetic testing has increased since the FDA approved the first gene therapy for IRDs in 2017. This study aimed to assess how the time to IRD clinical diagnosis and genetic testing has changed since gene therapy approval and increased access to no-cost genetic testing. It is important to confirm whether there has been and continues to be an extended diagnostic odyssey for IRD patients. 

Arriving at a confirmed clinical and genetic diagnoses can majorly impact IRD patients. Delaying these diagnoses could potentially result in unnecessary clinical examinations or referrals, missed or delayed opportunities to participate in research and clinical trials (or, in rare cases, an FDA-approved therapy), lack of understanding of inheritance pattern and recurrence risk during a patient’s reproductive years, delayed referral to specialists for ongoing care and management, and delayed access to patient supports and community resources.

Which findings are important to emphasize?

Overall, the average time from symptom onset to diagnosis was 6.1 years, and from diagnosis to genetic testing was 9.6 years, for a total diagnostic odyssey of nearly 16 years! Delayed diagnoses can have financial, medical, and psychosocial implications, so this finding alone is worth highlighting. An important takeaway from the study is that these patients’ diagnostic odyssey is, on average, several years long, which is something we should be working to reduce/eliminate.

We suspect that reductions in time to diagnosis and genetic testing are likely due to the increased availability of no-cost genetic testing and increased IRD awareness and education for ocular care providers. However, we did not capture data that would allow us to determine specifically what improved the time to diagnosis.

What issues remain persist for IRD diagnosis?

The biotech and genetic testing industries are constantly changing. The availability of no-cost or low-cost genetic testing options (typically sponsored by biopharma or by patient advocacy organizations) can change over time. In the past few months, we have seen changes to the two main sponsored IRD testing programs we use for our patients, which might mean that more patients have to attempt to get insurance coverage for genetic testing or pay out of pocket. Insurance coverage for genetic testing and counseling remains a major hurdle in all areas of genetics. With limitations to or potential future elimination of no-cost sponsored genetic testing programs for IRD patients, we may again see longer delays to genetic diagnoses.