Contributions
Abstract: EP1465
Type: Poster Sessions
Abstract Category: Pathology and pathogenesis of MS - Genetics/Epigenetics
Background: A number of multiple sclerosis (MS) risk common variants have been successfully identified through genome-wide association studies (GWAS), and they explain about 40% of the genetic predisposition to MS. Here, we aimed to identify new common variants associated with MS and investigate their potential functional implications in the disease.
Methods: Coding and regulatory regions of 14 MS-risk genes were resequenced using the Illumina Hiseq technology in 524 DNA samples from MS patients and 546 from healthy controls (HC). Raw data were mapped to the human reference genome (hg19) using the BWA aligner and variant discovery were performed with the HaplotypeCaller tool. Top associated variants were selected for validation in 3450 DNA samples from MS patients and 1688 from HC using the MassARRAY System (Agena Bioscience), and the top validated variant in the CXCR5 gene was chosen for further functional studies. Linkage disequilibrium (LD) analyses were performed to select variants in high LD (r2>0.5) with the top one and encountered variants were included in the successive studies. HEK cells were transfected with the pGL4.23-GW plasmid containing the insert under study and the CXCR5 gene promoter transcriptional activity was then assessed by luciferase reporter assays.
Results: Targeted resequencing revealed a total of 32 variants differentially distributed between MS patients and HC (p< 0.05), of which 9 polymorphisms within 7 genes were selected for further genotyping in an independent cohort of cases and controls. The following three polymorphisms were validated: rs10892307 (CXCR5, p=1.37×10-6, OR=0.76), rs2762943 (CYP24A1, p=0.047, OR=1.16) and rs1599932 (TSFM, p=0.001, OR=0.85). Variants rs3176905, rs11602393 and rs55756957 were in high LD with the most strongly associated variant, rs10892307, and hence were included in the luciferase assays. Statistical analysis demonstrated a modest but significant increased transcriptional activity of the minor alleles of rs11602393 and rs55756957 when compared with their respective major alleles in the forward orientation, showing a 2.16-fold (p=0.005) and a 1.75-fold (p=0.01) higher ratio of luciferase activity, respectively.
Conclusions: We report a novel association with MS susceptibility in the CXCR5 gene. Functional studies suggest that the rs11602393 and rs55756957 variants impair CXCR5 transcriptional activity and may explain the association of the rs10892307 variant with MS.
Disclosure: E. Gil-Varea, F. Matesanz, M. Fedetz, N. Spataro, S. Malhotra, A. Navarro, E. Bosch and A. Alcina report no disclosures.
X. Montalban has received speaking honoraria and travel expenses for scientific meetings, has been a steering committee member of clinical trials or participated in advisory boards of clinical trials in the past years with Bayer Schering Pharma, Biogen Idec, EMD Merck Serono, Genentech, Genzyme, Novartis, Sanofi-Aventis, Teva Phramaceuticals, Almirall and Roche.
M. Comabella has received compensation for consulting services and speaking honoraria from Bayer Schering Pharma, Merk Serono, Biogen-Idec, Teva Pharmaceuticals, Sanofi-Aventis, Genzyme and Novartis.
O. Fernández has received honoraria as consultant in advisory boards, and as chairmen or lecturer in meetings, and has also participated in clinical trials and other research projects promoted by Biogen-Idec, Bayer-Schering, Merck-Serono, Teva, Novartis, Roche, Allergan and Almirall.
A. Saiz has received compensation for consulting services and speaker honoraria from Bayer-Schering, Merck-Serono, Biogen-Idec, Sanofi-Aventis, Teva Pharmaceutical Industries Ltd and Novartis.
Ll. Ramió-Torrentà has received speaking honoraria and travel expenses for scientific meetings and has participated in advisory boards in the past years with Bayer Schering Pharma, Biogen, EMD Merck Serono, Sanofi Genzyme, Novartis, Sanofi-Aventis, Teva Phramaceuticals, Almirall and Roche.
G. Izquierdo received speaking honoraria from Almirall, Bayer, Biogen, Novartis, Merck and Roche.
Abstract: EP1465
Type: Poster Sessions
Abstract Category: Pathology and pathogenesis of MS - Genetics/Epigenetics
Background: A number of multiple sclerosis (MS) risk common variants have been successfully identified through genome-wide association studies (GWAS), and they explain about 40% of the genetic predisposition to MS. Here, we aimed to identify new common variants associated with MS and investigate their potential functional implications in the disease.
Methods: Coding and regulatory regions of 14 MS-risk genes were resequenced using the Illumina Hiseq technology in 524 DNA samples from MS patients and 546 from healthy controls (HC). Raw data were mapped to the human reference genome (hg19) using the BWA aligner and variant discovery were performed with the HaplotypeCaller tool. Top associated variants were selected for validation in 3450 DNA samples from MS patients and 1688 from HC using the MassARRAY System (Agena Bioscience), and the top validated variant in the CXCR5 gene was chosen for further functional studies. Linkage disequilibrium (LD) analyses were performed to select variants in high LD (r2>0.5) with the top one and encountered variants were included in the successive studies. HEK cells were transfected with the pGL4.23-GW plasmid containing the insert under study and the CXCR5 gene promoter transcriptional activity was then assessed by luciferase reporter assays.
Results: Targeted resequencing revealed a total of 32 variants differentially distributed between MS patients and HC (p< 0.05), of which 9 polymorphisms within 7 genes were selected for further genotyping in an independent cohort of cases and controls. The following three polymorphisms were validated: rs10892307 (CXCR5, p=1.37×10-6, OR=0.76), rs2762943 (CYP24A1, p=0.047, OR=1.16) and rs1599932 (TSFM, p=0.001, OR=0.85). Variants rs3176905, rs11602393 and rs55756957 were in high LD with the most strongly associated variant, rs10892307, and hence were included in the luciferase assays. Statistical analysis demonstrated a modest but significant increased transcriptional activity of the minor alleles of rs11602393 and rs55756957 when compared with their respective major alleles in the forward orientation, showing a 2.16-fold (p=0.005) and a 1.75-fold (p=0.01) higher ratio of luciferase activity, respectively.
Conclusions: We report a novel association with MS susceptibility in the CXCR5 gene. Functional studies suggest that the rs11602393 and rs55756957 variants impair CXCR5 transcriptional activity and may explain the association of the rs10892307 variant with MS.
Disclosure: E. Gil-Varea, F. Matesanz, M. Fedetz, N. Spataro, S. Malhotra, A. Navarro, E. Bosch and A. Alcina report no disclosures.
X. Montalban has received speaking honoraria and travel expenses for scientific meetings, has been a steering committee member of clinical trials or participated in advisory boards of clinical trials in the past years with Bayer Schering Pharma, Biogen Idec, EMD Merck Serono, Genentech, Genzyme, Novartis, Sanofi-Aventis, Teva Phramaceuticals, Almirall and Roche.
M. Comabella has received compensation for consulting services and speaking honoraria from Bayer Schering Pharma, Merk Serono, Biogen-Idec, Teva Pharmaceuticals, Sanofi-Aventis, Genzyme and Novartis.
O. Fernández has received honoraria as consultant in advisory boards, and as chairmen or lecturer in meetings, and has also participated in clinical trials and other research projects promoted by Biogen-Idec, Bayer-Schering, Merck-Serono, Teva, Novartis, Roche, Allergan and Almirall.
A. Saiz has received compensation for consulting services and speaker honoraria from Bayer-Schering, Merck-Serono, Biogen-Idec, Sanofi-Aventis, Teva Pharmaceutical Industries Ltd and Novartis.
Ll. Ramió-Torrentà has received speaking honoraria and travel expenses for scientific meetings and has participated in advisory boards in the past years with Bayer Schering Pharma, Biogen, EMD Merck Serono, Sanofi Genzyme, Novartis, Sanofi-Aventis, Teva Phramaceuticals, Almirall and Roche.
G. Izquierdo received speaking honoraria from Almirall, Bayer, Biogen, Novartis, Merck and Roche.