Two translocations of chromosome 15q associated with dyslexia
- Jaana Nopola-Hemmia,b,c,
- Mikko Taipaleb,
- Tuomas Haltiab,d,
- Anna-Elina Lehesjokib,
- Arja Voutilainena,
- Juha Kereb,e
- aDepartment of Paediatric Neurology, Hospital for Children and Adolescents, University of Helsinki, Finland, bDepartment of Medical Genetics, Haartman Institute, University of Helsinki, Finland, cDepartment of Paediatrics, Jorvi Hospital, Espoo, Finland, dDepartment of Medical Chemistry, Institute of Biomedical Sciences, University of Helsinki, Finland, eFinnish Genome Centre, PO Box 21 (Tukholmankatu 2), FIN-00014 University of Helsinki, Finland
- Professor Kere, juha.kere{at}helsinki.fi
- Revised 11 May 2000
- Accepted 20 June 2000
Abstract
Developmental dyslexia is characterised by difficulties in learning to read. As reading is a complex cognitive process, multiple genes are expected to contribute to the pathogenesis of dyslexia. The genetics of dyslexia has been a target of molecular studies during recent years, but so far no genes have been identified. However, a locus for dyslexia on chromosome 15q21 (DYX1) has been established in previous linkage studies. We have identified two families with balanced translocations involving the 15q21-q22 region. In one family, the translocation segregates with specific dyslexia in three family members. In the other family, the translocation is associated with dyslexia in one family member. We have performed fluorescence in situ hybridisation (FISH) studies to refine the position of the putative dyslexia locus further. Our results indicate that both translocation breakpoints on 15q map within an interval of approximately 6-8 Mb between markers D15S143 and D15S1029, further supporting the presence of a locus for specific dyslexia on 15q21.
