Genomics transforming diagnosis of inherited eye disorders

see Navigating the current landscape of clinical genetic testing for inherited retinal dystrophies

Until recently, clinicians faced with a difficult case of suspected congenital eye disease had limited diagnostic options. Visual-field testing can document progressive photoreceptor loss, but an understanding of the underlying cause of vision loss remained elusive. Today, modern genomics offers a panoply of individual genetic tests and broader genomic panels that provide many more diagnostic options for clinicians and patients. Indeed, few medical specialties have benefited more directly from the recent revolution in genomic technology than ophthalmology. Massively parallel sequencing has now been demonstrated to be a potent tool for diagnosing inherited eye disease, and the delineation of mutations that underlie diagnosis is becoming even more relevant owing to dramatic advances in gene therapy for such disorders.

In this themed issue, we present a cross-section of studies across a range of research in ophthalmic genetics. A review by Kristy Lee and Seema Garg of the University of North Carolina, Chapel Hill, provides a guide to navigating current clinical genetic testing options for detecting inherited retinal dystrophies. Over the past 25 years, more than 200 genes contributing to inherited retinal dystrophies have been identified, as the authors point out. One of the most widely distributed of these related disorders, retinitis pigmentosa (RP), represents not one but a group of inherited disorders of the eye’s photoreceptors, each of which can lead to progressive vision loss. RP affects 1 in 4,000 people worldwide. Numerous genomic regions can harbor genes linked to RP, and the pattern of inheritance may be autosomal dominant, autosomal recessive, or X linked, making it difficult to pinpoint a genetic cause. However, next-generation genomic panels can now provide an accurate diagnosis in many more cases. Commercially available panels include more than 100 genes known to be associated with syndromic and nonsyndromic retinal dystrophies. As the authors state, the advent of genomic testing for retinal disorders offers information to allow risk assessment for patients and their family members and to determine eligibility for inclusion in gene-based clinical trials.

Topics addressed by original research articles in this issue include unexpected diagnostic revisions made after comprehensive genomic analysis of patients with Stargardt macular dystrophy, the reproducibility of panel-based diagnostic testing for inherited eye diseases, and novel variants identified by whole-mitochondrial genome sequencing in primary open-angle glaucoma. —Jim Evans, Editor-in-Chief, and Karyn Hede, News Editor