Real-World Engagement with Free Genotyping by Patients with Inherited Retinal Disease in a Single Private Retinal Centre in Australia.

Purpose: Genotyping patients with inherited retinal diseases (IRD) is important for diagnosis, genetic counselling, and future treatments. However, in Australia less than 10% of patients with IRD have undergone genetic testing. Recognised barriers to testing include cost, access, and trust in the treating clinician. We aimed to assess uptake and outcomes to an offer of sponsored (free) genetic testing with home DNA collection, thereby removing typical barriers to genetic testing.

Methods: Participation in a sponsored genetic testing program (Invitae Corporation) was offered to adults from a private retinal practice in Australia in July 2022. Email invitations were sent to 233 patients clinically diagnosed with an IRD phenotype by the senior author. Potential participants were ≥18 years old, had no previous diagnostic genetic testing, and had supplied an email address for communication.

Results: Emails were successfully delivered to 205 individuals. Response rate to invitation were low, with no reply in the 62% cases (128/205). Of the 58 participants for whom testing was ordered, 47 (47/58, 81%) supplied at-home collected DNA. The solve rate was 34% (16/47), rising to 53% (25/47) when probable solves were included. One of the thirteen families accepted the offer of family studies to clarify the genotype. The most frequent identified IRD-associated gene was PRPH2 (4/16 cases), followed by RHO (2/16 cases).

Conclusion: Overall low response, DNA return and acceptance of family testing rates suggest ill-defined human factors affected DNA genetic testing uptake. Improved patient education and follow-up of offers of genetic testing are required to improve patient genotyping.