title: The genetic and environmental origins of language disability and ability.
abstract: This study investigated whether genes affect language impairment to the same extent as they affect differences in language ability following up an earlier study of 579 four-year-old twins with low language performance and their cotwins (Viding et al., in press). The present study selected low-language twins from 6,963 pairs of twins from the Twins Early Development Study assessed for vocabulary and grammar by their parents at 2, 3, and 4 years of age. For impaired groups corresponding to the lowest scoring 5% and 10% at each age, twin concordances and model-fitting analyses indicated substantial genetic influence on the mean difference between affected children and the population (h2g), generally higher than for individual differences for the entire sample (h2).
authors.affiliation: Department of Psychology, University of Bielefeld, Bielefeld, Germany. fspin@uni-bielefeld.de
authors.forename: Frank M
authors.initials: FM
authors.lastname: Spinath
authors.forename: Thomas S
authors.initials: TS
authors.lastname: Price
authors.forename: Philip S
authors.initials: PS
authors.lastname: Dale
authors.forename: Robert
authors.initials: R
authors.lastname: Plomin
mesh_terms: D002675:Child, Preschool; D004777:Environment; D005260:Female; D006801:Humans; D007805:Language Development Disorders / Q000175:diagnosis / Q000209:etiology / Q000235:genetics*; D008297:Male; D012720:Severity of Illness Index; D014427:Twins / Q000235:genetics