ABSTRACT
Despite advances in the characterization of developmental dyslexia (DD), several questions regarding the interplay between DD-susceptibility genes and environmental risk factors remain open. This systematic review aimed at answering the following questions: What has been the impact of new resources on the knowledge about DD? Which questions remain open? What is the investigative agenda for the short term? Forty-six studies were analyzed. Despite the growing literature on DD candidate genes, most studies have not been replicated. We found large effects on causative genes and smaller environmental contributions, involving maternal smoking during pregnancy, SES and the DYX1C1-1259C/G marker. Implications are discussed.
Acknowledgements
We want to thank Dr. Claudio S. Hutz for initial support and guidance on this work. We also would like to thank Dr. Anselmo J. Kamada for insightful contributions on data analysis and methodological tips.
Funding
This work was supported by Brazilian National Counsel of Technological and Scientific Development (CNPq-Brazil) and Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES-Brazil). The Brazilian National Counsel of Technological and Scientific Development (CNPq) funded the PhD scholarship to the first author and the senior researcher scholarships to the last four authors. The second, third and fouth authors receive a PhD scholarship from the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES-Brazil).