Abstract
Abstract: :
Purpose: To genetically map a three generation family of English descent and a four generation family from the French Canadian population of Quebec with retinitis pigmentosa (RP). RP is a highly heterogeneous group of genetic disorders of the retina causing progressive loss of peripheral vision and night blindness. The occurrence of the defect in the population is between 1:3000 and 1:7000 individuals. Method: Full clinical examination and pedigree data were collated. Ethical committee approval and informed consent was obtained from all participants. Methodology includes DNA extraction, microsatellite marker typing by PCR-based methods and linkage analysis. Results: To date we have genotyped 18 members of the English adRP family including 8 affected individuals, and 20 members of the Canadian family with 9 affecteds, with markers corresponding to the ten known adRP loci on autosomes 1q, 3q, 6p, 7p, 7q, 8cen, 14q, 17p, 17q and 19q. Preliminary results show exclusion of linkage (lodscore Z -2.50 to -6.40 at θ=0.0) in both families from all of the aforementioned loci. An effort to map novel disease-causing gene/s is underway using total genome scan and specific markers in regions of tentative linkage. Additional family members are also being recruited in order to strengthen these results. Conclusion: In this study we provide evidence for at least one novel disease locus for adRP. This is supportive of previously published data indicating the existence of additional adRP loci in the human genome. Once linkage is established, candidate genes from the corresponding genetic interval will be characterised and screened for mutations in affected members of the two adRP families.
Keywords: 562 retinal degenerations: hereditary • 457 linkage analysis • 335 candidate gene analysis