1. ¹Department of Psychiatry, Cell and Molecular Division, The Toronto Western Hospital, University Health Network, Toronto, Ontario, Canada
2. ²Brain and Behaviour Programme, The Hospital for Sick Children, Toronto, Ontario, Canada
3. ³The Centre for Addiction and Mental Health, Toronto, Ontario, Canada

Correspondence: Dr CL Barr, Department of Psychiatry, The Toronto Western Hospital, 399 Bathurst St., Room MP14-302, Toronto, ON M5T 2S8, Canada. E-mail: CBarr@uhnres.utoronto.ca

Received 3 December 2003; Revised 18 May 2004; Accepted 19 May 2004; Published online 13 July 2004.

Abstract

Dyslexia has been linked to a number of chromosomal regions including 15q. Recently a gene, EKN1, with unknown function in the linked region, was identified via a translocation breakpoint. This gene was further supported as a susceptibility locus by association studies in a Finnish sample. We investigated the possibility of this locus as a susceptibility gene contributing to dyslexia, analyzed as a categorical trait, and analyzed key reading phenotypes as quantitative traits using six polymorphisms including the two previously reported to be associated with dyslexia. In our sample of 148 families identified through a proband with reading difficulties, we found significant evidence for an association to dyslexia analyzed as a categorical trait and found evidence of association to the reading and related processes of phonological awareness, word identification, decoding, rapid automatized naming, language ability, and verbal short-term memory. However, association was observed with different alleles and haplotypes than those reported to be associated in a Finnish sample. These findings provide support for EKN1 as a risk locus for dyslexia and as contributing to reading component processes and reading-related abilities. Based on these findings, further studies of this gene in independent samples are now required to determine the relationship of this gene to dyslexia.