Purpose  

To present the clinical features of two brothers with molecularly confirmed X-linked juvenile retinoschisis (xlRS) but with non-characteristic electrophysiological findings.

Methods  

Comprehensive ophthalmological examinations were performed. The electroretinograms (ERGs) were recorded under ISCEV standards, and ERGs elicited by long-duration stimuli were also evaluated. Standard genetic analysis of peripheral blood leukocytes was performed.

Results  

Molecular testing revealed a novel 473-bp deletion including exon 4 in the XLRS1 gene in both siblings. This resulted in a frameshift mutation and a premature termination at codon 78. The scotopic and photopic ERGs were reduced, but the negative-type ERG, characteristic of xlRS, was not observed. Flicker ERGs were also highly reduced. Long-duration stimuli elicited ERGs with a complete loss of the b-wave and a preservation of the off-response, i.e., negative-type ERG. The phenotype/genotype relationship was not determined.

Conclusion  

The consistency of the ERGs elicited by long-duration stimuli in xlRS patients suggests that this type of stimuli provides responses that are a better indicator for the progression or stage of the disease.