Genetic Testing Leading to Early Identification of Childhood Ocular Manifestations of Usher Syndrome

Objectives Hearing-loss gene panel testing (HLGPT) is increasingly accessible as a first-line test in determining the etiology of sensorineural hearing loss (SNHL) in children. A major advantage of HLGPT is early identification of syndromic forms of SNHL, especially Usher syndrome, prior to the development of overt syndromic phenotype, which may impact management and counseling. Here, we describe early ocular findings in children with clinically non-syndromic SNHL identified by HLGPT as having two variants associated with Usher Syndrome. Methods A total of 184 children, ages 1 month - 15 years of age, evaluated at one tertiary pediatric children's hospital for clinically non-syndromic SNHL, underwent next-generation sequencing of 150 genes involved in hearing loss. Children with two variants in genes associated with Usher syndrome were referred for evaluation by pediatric ophthalmology. Results A total of 18/184 tested children had two variants in Usher syndrome-associated genes, including MYO7A, GPR98 (ADGRV1), USH2A, and PDZD7. SNHL varied from moderate to profound. 29% of the children who underwent clinical ophthalmology evaluation were found to have previously unidentified retinal abnormalities on retinal imaging or electroretinography consistent with inherited retinal degeneration. Conclusion Among this ethnically and racially diverse pediatric population with apparently non-syndromic SNHL, HLGPT yielded a high proportion (10%) of children with two variants in genes associated with Usher syndrome. Early genetic testing allows early identification of variants conferring a diagnosis of Usher syndrome at a stage prior to visual symptoms. This allows for more informed genetic counseling, reproductive planning, and sensory deficit interventions. Level of Evidence Level 4 Laryngoscope, 2020

Automated summary

HLGPT is increasingly used as a first-line test for determining the cause of SNHL in children. This study found that 29% of children with clinically non-syndromic SNHL had previously unidentified retinal abnormalities consistent with inherited retinal degeneration. Early genetic testing allows for early identification of Usher syndrome variants, informing genetic counseling and interventions.