Abstract
Purpose: :
To describe a novel locus in X chromosome resulting in a form of childhood RP, characterized by relatively early manifestation of night blindness, progressive loss of visual fields, and finally loss of central vision in affected males.
Methods: :
Ophthalmologic examination was performed in large Utah kindred. Genotyping to RP2, RP3, RP6, RP23 and RP24, and mutational screening of RP2 and RPGR were performed.
Results: :
The study pedigree spans 6 generations with 191 individuals. A total of 53 members including 13 affected males, 15 carriers and 25 unaffected representing four generations were examined and genotyped. Age of onset ranges from 5–8 years, VA range from 20/25 in children to LP in older adults. Linkage analysis using STR polymorphic markers encompassing candidate loci showed that none of above described five loci was associated with the phenotype in this kindred. Direct sequencing of RP2 and RPGR showed no mutation.
Conclusions: :
We describe large kindred with x–linked RP. A novel disease gene is most likely associated with the RP phenotype. Fine mapping and positional cloning is in progress. Identification of new gene for RP will increase our understanding of RP and provide potential new therapeutic avenues.
Keywords: retinal degenerations: hereditary • gene mapping