Evaluation of RP2 and RP3 genes in an X-linked RP family manifesting loss of central vision and preserved peripheral function

X-Linked retinitis pigmentosa is a most severe and heterogeneous disorder o f the retina. Recently, genes (RP2 and RPGR) from two X-linked loci have be en positionally cloned and mutations have been identified in many families. To further evaluate allelic and non-allelic heterogeneity and the genotype - phenotype relationships, and to determine the prevalence of mutations in the gene, we have analyzed one previously unreported X-linked retinitis pi gmentosa family, using a combination of haplotype analysis and DNA sequenci ng. Our extensive analysis of the RP2 gene failed to detect any disease - c ausing or polymorphic mutations. In the case of the RP3 gene, the alleles o f the dinucleotide repeat marker did not segregate with the disease. Althou gh we cannot completely exclude the possibility of the RP2 and RP3 genes as candidate genes, the above results suggest that structural and functional changes associated with the RP2 gene are not responsible for the phenotype in the family analyzed. Further identification of the X-linked genes may fa cilitate the elucidation of the molecular basis of the disorder in the fami ly analyzed.