Congenital hearing loss is associated with earlier visual decline in USH2A retinitis pigmentosa

Abstract

 

Purpose

 

USH2A mutations are an important cause of retinitis pigmentosa (RP) with or without congenital sensorineural hearing loss. The aim of this study is to investigate whether these two patient groups have a similar visual prognosis.

 

Methods

 

We included 126 consecutive patients with RP due to mutations in USH2A from multiple ophthalmogenetic clinics in the Netherlands and Belgium. Of these, 50 had a diagnosis of congenital hearing loss. All patients underwent regular eye examinations including best-corrected Snellen visual acuity (VA) and Goldmann visual fields (VF). Lifetime cumulative risk of low vision and blindness were estimated using Kaplan-Meier product-limit survival analysis. The definitions of low vision and blindness were based on VA and VF and were in accordance with WHO standards. The log-rank test was used to determine the statistical significance of risk differences.

 

Results

 

The follow up period was up to 40 years with a mean of 7.4 (±0.9) years; follow up did not differ between the patient groups (P=0.41). Patients with congenital hearing loss were younger at age of onset of RP (16.3 vs 27.9 years, P<0.001), but did not differ in gender (24/50 vs 34/75 males, P=0.76). They had a higher cumulative risk of visual impairment (risk at age 50: 46% vs 13%, P=0.004) and became visually impaired approximately 10 years earlier (median age 53 vs 63 years, P=0.004 for low vision) than patients without congenital hearing loss.

 

Conclusions

 

Most patients with RP due to USH2A develop severe visual impairment by middle age. However, those with congenital hearing loss have a faster decline and a higher cumulative risk of visual impairment than those without. Loss of function of the USH2A protein usherin may be more severe in those with a congenital onset of hearing loss. Our data aid in patient counseling by clinicians and geneticists, and can be valuable information for researchers of gene-based therapy.  

 

Cumulative risk of visual impairment and blindness in patients with RP due to USH2A mutations with and without congenital hearing loss.