Mutation Detection in Patients with Retinal Dystrophies Using Targeted Next Generation Sequencing

Abstract

Retinal dystrophies (RD) constitute a group of blinding diseases that are characterized by clinical variability and pronounced genetic heterogeneity. The different nonsyndromic and syndromic forms of RD can be attributed to mutations in more than 200 genes. Consequently, next generation sequencing (NGS) technologies are among the most promising approaches to identify mutations in RD. We screened a large cohort of patients comprising 89 independent cases and families with various subforms of RD applying different NGS platforms. While mutation screening in 50 cases was performed using a RD gene capture panel, 47 cases were analyzed using whole exome sequencing. One family was analyzed using whole genome sequencing. A detection rate of 61% was achieved including mutations in 34 known and two novel RD genes. A total of 69 distinct mutations were identified, including 39 novel mutations. Notably, genetic findings in several families were not consistent with the initial clinical diagnosis. Clinical reassessment resulted in refinement of the clinical diagnosis in some of these families and confirmed the broad clinical spectrum associated with mutations in RD genes.

Fig 1. Pedigrees of six families discussed in detail in the manuscript.

The arrows indicate the patients in whom NGS was performed. Family number and disease-causing mutation(s) are noted above each pedigree. The diagnosis of the patient and the genotype for each mutation are listed below each individual´s symbol. LCA, Leber congenital amaurosis; BBS, Bardet Biedl syndrome; CRD, cone-rod dystrophy; RP, retinitis pigmentosa; ACHM, achromatopsia; ADOAC, autosomal dominant optic atrophy and cataract.