PURPOSE: X-linked retinoschisis (RS) is a degenerative disorder that causes peripheral vision loss from splitting of the retina through the nerve fiber layer and impairs central vision due to parafoveal cysts. Previous mapping localized RS to a 3.7 cM genetic interval at Xp22.1-p22.2. We have studied additional new RS families to refine the genetic mapping of RS. New markers near the RS locus were used. METHODS: Fourteen microsatellite and RFLP markers were used for linkage analysis of approximately 150 meioses in 17 RS pedigrees. Standard PCR protocols and RFLP detection methods were used, and haplotypes were constructed. RESULTS: Seven individuals showed recombinations in the RS region, of which four were distal and three were proximal to RS. A female carrier with two affected sons showed a recombination distal to RS with DXS987, DXS207, DXS43, DXS1195 and DXS418. Another individual showed a chromosomal crossover proximal to RS with DXS41, DXS274, DXS1226, DXS1052 DXS443 and AFM291wf5. This localizes RS between (DXS1195 and DXS418) and AFM291wf5. CONCLUSIONS: Our study defines a small genetic interval for RS within a physical distance of approximately 900-1000Kb. The flanking markers (DXS1195 and DXS418) and AFM291wf5 are contained on a single 2Mb YAC 939h7, along with DXS999 which others report to show a recombination proximal to RS; our critical individual was not informative at this locus. Our results order these loci as Xptel - (DXS987,DXS207,DXS1053,(DXS43)) - HDXS1195,DXS418) - (RS,DXS999) - (AFM291wf5,DXS443) - DXS1052 - (DX31226,DXS274,DXS41) - Xcen. We are screening YAC 939h7 and smaller YACs from the region for expressed sequences using exon trapping and direct cDNA selection to identify candidate genes for RS.
|Original language||English (US)|
|Journal||Investigative Ophthalmology and Visual Science|
|State||Published - Feb 15 1996|
ASJC Scopus subject areas
- Sensory Systems
- Cellular and Molecular Neuroscience