PurposeNext-generation sequencing (NGS) based methods are being adopted broadly for genetic diagnostic testing, but the performance characteristics of these techniques have not been fully defined with regard to test accuracy and reproducibility.MethodsWe developed a targeted enrichment and NGS approach for genetic diagnostic testing of patients with inherited eye disorders, including inherited retinal degenerations, optic atrophy and glaucoma. In preparation for providing this Genetic Eye Disease (GEDi) test on a CLIA-certified basis, we performed experiments to measure the sensitivity, specificity, reproducibility as well as the clinical sensitivity of the test.ResultsThe GEDi test is highly reproducible and accurate, with sensitivity and specificity for single nucleotide variant detection of 97.9% and 100%, respectively. The sensitivity for variant detection was notably better than the 88.3% achieved by whole exome sequencing (WES) using the same metrics, due to better coverage of targeted genes in the GEDi test compared to commercially available exome capture sets. Prospective testing of 192 patients with IRDs indicated that the clinical sensitivity of the GEDi test is high, with a diagnostic rate of 51%.ConclusionThe data suggest that based on quantified performance metrics, selective targeted enrichment is preferable to WES for genetic diagnostic testing.

Mutations in the CRB1 gene are associated with variable phenotypes of severe retinal dystrophies, ranging from Leber Congenital Amaurosis (LCA) to rod-cone dystrophy (also called retinitis pigmentosa (RP)). Moreover, retinal dystrophies resulting from CRB1 mutations may be accompanied by specific fundus features: preservation of the para-arteriolar retinal pigment epithelium (PPRPE) and retinal telangiectasia with exudation (also referred to as Coats-like vasculopathy). In this publication we report seven novel mutations and classify over 150 reported CRB1 sequence variants that were found in more that 240 patients. The data from previous reports was used to analyse a potential correlation between CRB1 variants and the clinical features of respective patients. This meta-analysis suggests that the differential phenotype of patients with CRB1 mutations is due to additional modifying factors rather than particular mutant allele combination.