Chromosome 6p influences on different dyslexia-related cognitive processes: Further confirmation

In this study, which is a continuation and an extension of an earlier study , we enrolled two new families (N = 31) and recruited more individuals from the previously ascertained families (N = 56). The eight multiplex families (N = 171) presented in this study were ascertained from a sample of adult probands whose childhood reading history is well documented through archiva l information. Six: phenotypes were constructed to span a range of dyslexia -related cognitive processes. These phenotypes were (1) phonemic awareness (of spoken words); (2) phonological decoding (of printed nonwords); (3) rap id automatized naming (of colored squares or object drawings); (4) single-w ord reading (orally, of printed real words); (5) vocabulary; and (6) spelli ng (of dictated words). Ln addition, the diagnosis of lifelong dyslexia was established by clinical means. Genotyping was done with nine highly polymo rphic markers from the 6p22.3-6p21.3 region. The results of two- and multip oint identity-by-descent and identity-by-state analyses supported the impor tance of a putative locus in the D6S464-D6S273 region for a number of dysle xia-related cognitive deficits.