Linkage disequilibrium and positional candidate gene analyses of a susceptibility locus for Reading Disability on chromosome 15q

We have identified a region for Reading Disability (RD) on chromosome 15q by linkage disequilibrium mapping (LD). Last year, we reported a significant association between RD and a three-marker haplotype (D15S146/D15S214/ D15S994: empirical p<0.001) in a sample of 103 parent/ RD proband trios. We have now replicated this finding in a second sample of 77 trios (p = 0.009, empirical p = 0.006). We have also identified a series of BACs that map to this region from which we have identified around 20 candidate genes using the NIX program (Identify unknown nucleic sequence; http://www.hgmp.mrc.ac.uk/NIX/). Three of these genes are involved in regulating neurotransmission, and one is a member of a gene family with another family member mapping to our candidate region for RD on chromosome 6 (abstract at this meeting by Turic and colleagues). We report here our replicated LD data, and the results to date of our analyses of these candidate genes.