Genetic etiology of spelling deficits in the Colorado and London twin studies of reading disability

✍ Scribed by J. C. Defries; Jim Stevenson; Jacquelyn J. Gillis; Sally J. Wadsworth

• Publisher: Springer Netherlands
• Year: 1991
• Tongue: English
• Weight: 889 KB
• Volume: 3
• Category: Article
• ISSN: 0922-4777
• DOI: 10.1007/bf00354962

✦ Synopsis

AF#lRAcT:

The basic multiple regression model for the analysis of selected twin data (DeFries and Fulker 1985, 1988) was fitted to spelling data from 100 pairs of MZ twins and 71 pairs of same-sex DZ twins tested in the Colorado Reading Project (DeFries, Olson, Pemrington and Smith 1991), and to data from 12 pairs of MZ twins and 15 pairs of same-sex DZ twins tested in the London twin study of reading disability (Stevenson, Graham, Fredman and McLoughlii 1984, 1987). Estimates of hi obtained from analyses of these data suggest that about 60% of the deficit of probands is due to heritable influences in both samples. When a regression model was fitted separately to data from males and females in the combined Colorado and London samples, resulting estimates of hi were 0.66 f 0.18 and 0.56 f 0.19, respectively, a nonsignificant difference. Collaborative analyses of data from additional twin studies of reading disability would facilitate more rigorous tests of hypotheses of differential genetic etiology as a function of group membership.