Javier Gayan1, S. D. Smith2, S. S. Cherny1,3, L. R. Cardon4, D. W. Fulker1,3, W. J. Kimberling2, R. K. Olson1, B. F. Pennington5, & J. C. DeFries1.
Reading disability (RD), or dyslexia, is a complex cognitive disorder manifested by difficulties in learning to read in otherwise normal individuals. Reading-disabled subjects exhibit deficits in several reading and language skills. Previous research has suggested the existence of a quantitative trait locus (QTL) for RD on the short arm of chromosome 6. In the present study, RD subjects' performance in several measures of word recognition and component skills of orthographic coding, phonological decoding, and phonological awareness, were individually subjected to QTL analysis with a new sample of 126 sib pairs, using a multipoint mapping method and 8 informative DNA markers on chromosome 6 (D6S461, D6S276, D6S258, D6S306, D6S105, D6S439, D6S291, D6S1019). The results indicate that there is significant linkage in the region of the first five markers for deficits in orthographic and phonological skills, providing a confirmation of previous findings.
Address: Javier Gayan, Institute for Behavioral Genetics, University of Colorado, Boulder, CO 80309-0447, Phone: 303 492 2817, Fax: 303 492 8063, Email: gayan@colorado.edu
1Institute for Behavioral Genetics, University of Colorado, Boulder, CO 80309-0447. 2Center for Hereditary Communication Disorders, Boys Town National Research Hospital, Omaha, NE 68131. 3Social, Genetic and Developmental Psychiatry Research Centre, Institute of Psychiatry, London, UK SE5 8AF. 4Sequana Therapeutics, La Jolla, CA 92037. 5Department of Psychology, University of Denver, Denver, CO 80208. 6Supported by NICHD Grants HD-11681 and HD-27802, and RO1 HD-22223.