The Current State of Genetic Testing Platforms for Inherited Retinal Diseases

Abstract

Purpose: To evaluate genetic testing platforms used to aid in the diagnosis of inherited retinal degenerations (IRDs).

Design: Evaluation of diagnostic tests and technologies.

Subjects: Targeted genetic panel testing for IRDs.

Methods: Data collected regarding targeted genetic panel testing for IRDs offered by different laboratories were investigated for the inclusion of coding and noncoding variants in disease genes. Both large IRD panels and smaller, more focused, disease-specific panels were included in the analysis.

Main outcome measures: Number of disease genes tested as well as the commonality and uniqueness across testing platforms in both coding and noncoding variants of disease.

Results: Across the 3 IRD panel tests investigated, 409 unique genes are represented, of which 269 genes are tested by all 3 panels. The top 20 genes known to cause over 70% of all IRDs are represented in the 269 common genes tested by all 3 panels. In addition, 138 noncoding variants in 50 unique genes are assayed across the 3 platforms. Focused, disease-specific panels exhibit significant variability across the 5 testing platforms that were studied.

Conclusions: Ordering genetic testing for IRDs is not straightforward, as evidenced by the multitude of panels available to providers. It is important that there is coverage of both coding and noncoding regions in IRD genes to offer diagnoses in these patients. This paper details the diversity of testing platforms currently available to clinicians and provides a thorough explanation of the genes tested in the different IRD panels. In a time of increased importance of the clinical genetic testing of patients with IRDs, knowledge of the proper test to order is paramount.

Keywords: Genetic counseling; Genetic testing; Genome sequencing; Inherited retinal disease; Retinal dystrophy.