Panel-based clinical genetic testing in 85 children with inherited retinal disease

Purpose: To assess the clinical usefulness of genetic testing in a pediatric population with inherited retinal disease (IRD).
Design: Single-center retrospective case series.
Participants: Eighty-five unrelated children with a diagnosis of isolated or syndromic IRD who were referred for clinical genetic testing between January 2014 and July 2016.
Methods: Participants underwent a detailed ophthalmic examination, accompanied by electrodiagnostic testing (EDT) and dysmorphologic assessment where appropriate. Ocular and extraocular features were recorded using Human Phenotype Ontology terms. Subsequently, multigene panel testing (105 or 177 IRD-associated genes) was performed in an accredited diagnostic laboratory, followed by clinical variant interpretation.
Main Outcome Measures: Diagnostic yield and clinical usefulness of genetic testing.
Results: Overall, 78.8% of patients (n ¼ 67) received a probable molecular diagnosis; 7.5% (n ¼ 5) of these had autosomal dominant disease, 25.4% (n ¼ 17) had X-linked disease, and 67.2% (n ¼ 45) had autosomal recessive disease. In a further 5.9% of patients (n ¼ 5), a single heterozygous ABCA4 variant was identified; all these participants had a spectrum of clinical features consistent with ABCA4 retinopathy. Most participants (84.7%; n ¼ 72) had undergone EDT and 81.9% (n ¼ 59) of these patients received a probable molecular diagnosis. The genes most frequently mutated in the present cohort were CACNA1F and ABCA4, accounting for 14.9% (n ¼ 10) and 11.9% (n ¼ 8) of diagnoses respectively. Notably, in many cases, genetic testing helped to distinguish stationary from progressive IRD subtypes and to establish a precise diagnosis in a timely fashion.
Conclusions: Multigene panel testing pointed to a molecular diagnosis in 84.7% of children with IRD. The diagnostic yield in the study population was significantly higher compared with that in previously reported unselected IRD cohorts. Approaches similar to the one described herein are expected to become a standard component of care in pediatric ophthalmology.We propose the introduction of genetic testing early in the diagnostic pathway in children with clinical and/or electrophysiologic findings, suggestive of IRD.