Relatively preserved retinal function in RPE65-associated retinopathy: a case report

RPE65-associated retinopathy is a rare form of inherited retinal dystrophy. This case report aimed to describe a patient with biallelic RPE65 variants who demonstrated a milder phenotype compared to previous cases.

A 9-year-old male patient was referred to The Jikei University Hospital for clinical and genetic assessments. The patient underwent ophthalmic examinations, including full-field electroretinography (ERG) in the left eye (LE) and in right eye (RE) after 30 min and 24 h of dark adaptation, respectively, and genetic testing using whole exome sequencing analysis. The genetic analysis revealed a known variant [(c.1543C > T, p.Arg515Trp)] and a novel variant [c.462G > T, (p.Lys154Asn)] in the compound heterozygous state in the RPE65 gene. Fundus photograph showed a normal appearance at the posterior pole and multiple white dots in the midperipheral retina. Fundus autofluorescence imaging showed diffusely decreased autofluorescence. Optical coherence tomography showed a normal appearance, including the outer retinal layers. Dark-adapted (DA) ERGs. (DA 0.01, DA 3.0, and DA 10.0) were reduced in amplitude in both eyes (BE), whereas a slight recovery of amplitude was observed in the RE. The b/a-wave ratios of DA 3.0 and 10.0 were 1.31 and 1.30 in the RE, and 1.16 and 1.25 in the LE. Light-adapted ERGs (LA 3.0 and LA 30-Hz flicker) were also reduced in amplitude in BE.

Our findings suggest that RPE65-associated retinopathy should be considered in the differential diagnosis, even in patients with preserved retinal structure and function.