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Purpose Autosomal dominant retinitis pigmentosa (adRP) affects approximately 1 in 12,000 individuals. To date, 24 adRP genes have been identified accounting theoretically for 44.7% of adRP families; therefore, genetic defects in many patients are yet to be identified. This study was intended to provide information on prevalence of known adRP genes in France and to localize new genes and loci. Methods The 10 most frequently mutated adRP genes (in full for RHO and RDS, in hot spots only for PRPF31, RP1, PRPF8, IMPDH1, NRL, PRPF3, NR2E3 and SNRNP200) were screened by systematic sequencing to determine the causative mutation in a cohort of 232 French families affected by adRP. We also performed a pilot experiment on 12 families by using whole exome sequencing (WES). Results The direct sequencing approach was performed on 232 proband DNAs. A causative mutation was found for 99 families (42.7 %), among which 35 out of 68 (51.5 %) were novel. Among the 133 remaining families with no mutation (57.3 %), 12 probands were subjected to WES. This allowed to identify 7 additional families with a causative mutation. Conclusion The prevalence of the genes was similar to that of the literature for most genes (e.g. RHO with 16 %), but were unexpected for others (e.g. NR2E3 with 3.9 %). The WES approach allowed us to identify a causative gene in 58.3 % of a population previously screened by direct sequencing approach. The 5 remaining families, negative with WES screen, are potentially carrying a mutation in one or more new adRP genes although an intronic mutation cannot be excluded. These 5 families are under active investigation. [ABSTRACT FROM AUTHOR]

Purpose Autosomal dominant retinitis pigmentosa (adRP) affects approximately 1 in 12,000 individuals. To date, 21 adRP genes have been identified accounting theoretically for 44.7% of adRP families; therefore, genetic defects in many patients are yet to be identified. This study was intended to provide information on prevalence of known adRP genes in France and to localize new genes and loci. Methods Microsatellite markers for the 21 adRP genes were used to genotype large families. Non excluded genes were then sequenced. For some families, we performed a whole‐genome SNP analysis using Affymetrix 250K or 6.0 chips. For small families, the 8 most frequently mutated adRP genes were sequenced (in full for RHO, in hot spots only for PRPF31, RDS, RP1, PRPF8, IMPDH1, NRL and PRPF3). Results Hitherto 18 adRP families were studied by indirect genotype analysis. Of these, 15 have shown mutations in known genes and 2 are still in progress. For the last family, one new locus was identified by whole‐genome SNP analysis and confirmed by microsatellite genotyping defining a 43‐Mb locus on chromosome 2. The direct sequencing approach was performed on 143 proband DNAs (completely for the first 50 patients and only RHO for the 93 other patients). A causative mutation was found for 20 families (14%), among which 9 out of 11 were novel. Conclusion The preliminary results, on this limited cohort, showed that the prevalence of known genes is probably underestimated in the literature because the causative mutation was found for 15 families out of 18 (83%). However one new locus has been identified and is under active investigation. [ABSTRACT FROM AUTHOR]