Novel 473-bp deletion in XLRS1 gene in a Japanese family with X-linked juvenile retinoschisis.
OBJECTIVE
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.


CONCLUSIONS
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.
Shinoda
Kei
K
Department of Ophthalmology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku 160-8582, Tokyo, Japan. shinodak@uni.de
Ohde
Hisao
H
Ishida
Susumu
S
Inoue
Makoto
M
Oguchi
Yoshihisa
Y
Mashima
Yukihiko
Y
D000328:Adult; D001483:Base Sequence; D004252:DNA Mutational Analysis; D004596:Electroretinography; D005091:Exons / Q000235:genetics; D005136:Eye Proteins / Q000235:genetics*; D016368:Frameshift Mutation; D006801:Humans; D007564:Japan; D008297:Male; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D012160:Retina / Q000503:physiopathology; D041441:Retinoschisis / Q000235:genetics* / Q000503:physiopathology; D017384:Sequence Deletion / Q000235:genetics*; D035781:Siblings
D005136:Eye Proteins; C108726:RS1 protein, human