Association of clinical features of X linked juvenile retinoschisis with new mutations in XLRS1 gene in Chinese families

Background The main cause of X linked juvenile retinoschisis is mutation of RS1 gene.The phenotype of X linked juvenile retinoschisis is associated with the mutation types of RS1 gene.However,the relationship of genotype and phenotype of X linked juvenile retinoschisis is unclear.Objective The present study was to survey the clinical phenotype of X-linked juvenile retinoschisis in twelve Chinese families with eleven different mutations in the XLRS1 gene. Methods Complete ophthalmic examinations with slit lamp biomicroscopy,fundus examination and Dhotography were carried out in 28 affected males.Ganzfeld electroretinography (ERG),fundus fluorescein angiography,A and B-scan standardized echography and optical coherence tomography(OCT)were also performed in some patients.The coding regions of the XLRS1 gene that encodes retinoschisin were amplified by polymerase chain reaction(PCR)and analyzed by the single strand conformation polymorphism(SSCP)assay.The RS1 gene mutations were determined by direct sequencing in an automated sequencer.Written informed consent wasobtained prior to the survey. Results The 28 affected males showed a typical foveal schisis with or without peripheral retinoschisis.The typical response to white single flash ERG was seen with a reduction of the b-wave amplitude and a relative preservation of the a-wave amplitude.causing a reduced b/a ratio in the male patients.A total of eleven different XLRS1 mutations in 12 families were identified,four of these mutations,including one frameshift mutaion(22 del T)of exon 1,Asp145His,Arg156Gly and Trp163X mutations of exon 5,were first described in this survey.One non-disease-related polymorphism(NSP),or the 576C to T(Pro192Pro)change of exon 6 was also newly reported herein.In the families with a frameshift(22 del T)mutation of exon 1,a splice donor site mutation(IVS1+2T Key words: Juvenile retinoschisis; XLRS1 gene; Mutation; Genotype; Phenotype