Genotypic Analysis of X-linked Retinoschisis in Western Australia

X-linked Retinoschisis is a leading cause of juvenile macular degeneration. Four Western Australian families affected by X-Linked Retinoschisis were analysed using DNA and clinical information from the Australian Inherited Retinal Disease (IRD) Register and DNA Bank. By direct sequencing of the RS1 gene, three genetic variants were identified; 52+1G>T, 289T>G and 416delA. 289T>G has not been previously reported and is likely to cause a substitution of a membrane binding residue (W92G) in the functional discoidin domain. All clinically diagnosed individuals showed typical electronegative ERGs. The 52+1G>T obligate carrier also recorded a bilaterally abnormal rod ERG and mildly abnormal photopic responses. mfERG trace arrays showed reduced response densities in the paramacular region extending futher temporally for each eye. Further analyses are currently underway for Stargardt's disease, autosomal dominant and autosomal recessive retinitis pigmentosa, and Leber's congenital amaurosis.