Project Description:
Specific reading disability (dyslexia) has been shown to be influenced by genes at several loci, including regions on chromosomes 1, 2, 3, 6, 13, 15, and 18. Children with dyslexia often have other comorbid disorders including speech sound disorder (SSD), specific language disability (SLI), and attention deficit-hyperactivity disorder (ADHD). This raises the question as to whether these comorbidities are due to coincidental occurrence of fairly common disorders, or if one disorder is a secondary effect of presence of the other disorder, or if both conditions can result from the same cause. This study is designed to test the third hypothesis, specifically whether loci that affect dyslexia also influence SSD. Preliminary evidence from our lab supports linkage of SSD to markers on chromosomes 1, 6, and 15 which also show linkage to reading disability, suggesting that the same genes can affect both phenotypes. Since reading disability is primarily a phonologic disorder, this implies that SSD also has a phonologic basis, rather than a motoric basis as has been hypothesized. This study tests whether those linkages are confirmed in a larger sample, and a full genome screen will be done to identify other loci with an effect on SSD. These loci would be compared to those identified for dyslexia, ADHD, and SLI to identify genes that affect only SSD or which affect comorbid traits as well. Accomplishing this goal will contribute to understanding the relation between spoken and written language development.
Unserved or Under-served Populations:
Racial or Ethnic Minorities, Disadvantaged Circumstances, Specific Groups
