Mapping And Identification Of DI Saese-Causing Genes For Bardet-Biedl Syndrome

Objective: we collected several Chinese families with Bardet–Biedl Syndrome, and performed linkage analysis and sequencing analysis, in order to identify new genes/loci or find new mutation for known gene(s), and Bardet–Biedl Syndrome.Methods: 1.Several Bardet–Biedl Syndrome families were collected, blood samples of family members were obtained, and DNA were extracted, the clinical data and samples data base were established. 2. Amplification for sequencing analysis by using special primers for known gene(s) was performed to exclude the known gene(s), linkage analysis for several microsatellite markers which tightly encompass the known gene(s) and loci were performed to exclude the known loci. 3. If the known gene(s) and loci were excluded, the genome-wide scan were performed for a novel locus: 382 STR(short tandom repeat)markers(ABI PRISM Linkage Mapping Sets V2.5-MD)were amplified for linkage analysis. 4. Specific software was used to calculate the lod Score value ( LOD value, which indicates the possibility of disease gene linked to the specific locus.) which based on the allele (haploid) typing result with two-point method to definite the positive loci by the largest LOD value. 5. The fluorescence STR were used to perform further genotyping analysis, in order to find a exact linkage locus and narrow down the MGI( Minimum Genetic Interval). Candidate gene approach was used to identified the disease-causing gene and mutation .Results: 1. Collected clinical and genetic information of two Bardet–Biedl Syndrome. 2. Completed the sequencing analysis for Bardet–Biedl Syndrome known gene(s), excluded the known gene(s), completed the genetic linkage analysis for known gene(s) and loci, the LOD score of most of these STR markers are less than 0 whenθ=0.0, several markers'LOD>0, but when add several flank markes , the LOD<0, then excluded the known gene ( s ) and loci. 3. Completed the genome-wide scan of STR(short tandom repeat markers)for the 2 pedigrees. 4. Found several positive loci, respectively on the 4th chromosome for 1046, the LOD score of these loci are all more than 1 whenθ=0.0, prompted the possibility of linkage in these loci. Found 1 positive loci, respectively on the 5th chromosome for 1022, the LOD score of these loci are more than 1 whenθ=0.0, prompted the possibility of linkage in these loci. 5. Included the loci on 4st for 1046. Completed sequencing analysis for 2 genes in possible locus on 4nd chromosome, and haven found a new mutations, identifying the disease gene for this family is in progress.Conclusion: 1.Established clinical and genetic information of two Bardet–Biedl Syndrome families, applied new genetic information for Bardet–Biedl Syndrome. 2. Completed a Bardet–Biedl Syndrome families (Bardet-Biedl Syndrome, BBS) disease is known family BBS7 gene sequencing and positioning of the chain, found the new gene is known mutation. 3.The other BBS families completion of a genetic disease gene family known BBS5 chain positioning, sequencing work is in progress. 4. The conclusion of this study have important academic value, and have a important role in gene screening, gene diagnosis and gene therapthy.