SCREENING FOR MULTIPLE GENES INFLUENCING DYSLEXIA

Genetic linkage analysis is a means of localizing genes to specific chromosomal regions. Localization of genes influencing specific reading disability (dyslexia) can lead to characterization of the phenotypic effects of each gene and to early diagnosis of children at risk. Previous studies using the family study LOD score method of linkage analysis have identified two chromosomal regions that may contain genes influencing dyslexia. The present study examines the sib pair method of linkage analysis, which has several advantages over the LOD score method. In particular, the mode of inheritance does not need to be specified and diagnosis of parents is not required, but it is a less powerful technique. Using the same population as the previous studies (with less than 200 sib pairs) and two different means of diagnosis of dyslexia, the sib pair analysis was able to detect the same suggested linkages as the LOD score method, plus a possible third region. This confirms that the sib pair method is an effective means of screening for linkage with reasonable sample sizes.