title: Xq27 FRAXA locus is a strong candidate for dyslexia: evidence from a genome-wide scan in French families.
abstract: Dyslexia is a frequent neurodevelopmental learning disorder. To date, nine susceptibility loci have been identified, one of them being DYX9, located in Xq27. We performed the first French SNP linkage study followed by candidate gene investigation in dyslexia by studying 12 multiplex families (58 subjects) with at least two children affected, according to categorical restrictive criteria for phenotype definition. Significant results emerged on Xq27.3 within DYX9. The maximum multipoint LOD score reached 3,884 between rs12558359 and rs454992. Within this region, seven candidate genes were investigated for mutations in exonic sequences (CXORF1, CXORF51, SLITRK2, FMR1, FMR2, ASFMR1, FMR1NB), all having a role during brain development. We further looked for 5'UTR trinucleotide repeats in FMR1 and FMR2 genes. No mutation or polymorphism co-segregating with dyslexia was found. This finding in French families with Dyslexia showed significant linkage on Xq27.3 enclosing FRAXA, and consequently confirmed the DYX9 region as a robust susceptibility locus. We reduced the previously described interval from 6.8 (DXS1227-DXS8091) to 4 Mb also disclosing a higher LOD score.
authors: UMR INSERM U930, François Rabelais University, Tours, France. m.huc-chabrolle@chu-tours.fr
authors: M
authors: M
authors: Huc-Chabrolle
authors: C
authors: C
authors: Charon
authors: A
authors: A
authors: Guilmatre
authors: P
authors: P
authors: Vourc'h
authors: G
authors: G
authors: Tripi
authors: M A
authors: MA
authors: Barthez
authors: E
authors: E
authors: Sizaret
authors: R A
authors: RA
authors: Thepault
authors: S
authors: S
authors: Le Gallic
authors: J
authors: J
authors: Hager
authors: A
authors: A
authors: Toutain
authors: M
authors: M
authors: Raynaud
authors: C
authors: C
authors: Andres
authors: D
authors: D
authors: Campion
authors: F
authors: F
authors: Laumonnier
authors: F
authors: F
authors: Bonnet-Brilhault
mesh_terms: D002648:Child; D041321:Chromosomes, Human, X / Q000235:genetics*; D004410:Dyslexia / Q000235:genetics*; D005260:Female; D051860:Fragile X Messenger Ribonucleoprotein 1 / Q000235:genetics*; D005602:France; D050172:Genes, X-Linked; D056426:Genetic Loci; D020022:Genetic Predisposition to Disease / Q000235:genetics*; D055106:Genome-Wide Association Study; D005838:Genotype; D006801:Humans; D008126:Lod Score; D008297:Male; D010375:Pedigree; D020641:Polymorphism, Single Nucleotide
chemical_list: D051860:Fragile X Messenger Ribonucleoprotein 1; C497683:FMR1 protein, human