Differential Genetic Etiology of Reading Difficulties as a Function of IQ: An Update

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• 作者：S. J. Wadsworth ; R. K. Olson and J. C. DeFries
• 关键词：Genetics ; Reading disability ; Dyslexia ; IQ ; General cognitive ability ; Twin studies
• 刊名：Behavior Genetics
• 出版年：2010
• 出版时间：November 2010
• 年：2010
• 卷：40
• 期：6
• 页码：751-758
• 全文大小：210.5 KB

文摘

In order to test the hypothesis that the genetic etiology of reading disability differs as a function of IQ, composite reading performance data from 308 pairs of identical (monozygotic, MZ) twins and 440 pairs of fraternal (dizygotic, DZ) twins (254 same-sex and 186 opposite-sex) in which at least one member of each pair was classified as reading-disabled were subjected to multiple regression analysis (DeFries and Fulker, Behav Genet 15:467–473, 1985; Acta Genet Med Gemellol 37:205–216, 1988). In the total sample, heritability of the group deficit in reading performance (h_g2) was .61 (¡À.06). However, results of fitting an extended regression model to reading performance and IQ data suggested that the genetic etiology of reading disability differs as a linear function of IQ (p ≤ .04). When the basic regression model was fitted separately to data from twin pairs with Wechsler (Examiner's manual: Wechsler intelligence scale for children—revised, 1974; Examiner's manual: Wechsler adult intelligence scale—revised, 1981) Full Scale IQ scores in the upper and lower 25 % of the sample, resulting estimates of h_g2 were .75 (¡À.12) and .50 (¡À.10), respectively (p ≤ .045). These results suggest that reading difficulties in children with a higher IQ are due substantially to genetic influences and may require intensive remediation efforts.