title: Gene x Environment interactions in speech sound disorder predict language and preliteracy outcomes.
abstract: Few studies have investigated the role of gene x environment interactions (G x E) in speech, language, and literacy disorders. Currently, there are two theoretical models, the diathesis-stress model and the bioecological model, that make opposite predictions about the expected direction of G x E, because environmental risk factors may either strengthen or weaken the effect of genes on phenotypes. The purpose of the current study was to test for G x E at two speech sound disorder and reading disability linkage peaks using a sib-pair linkage design and continuous measures of socioeconomic status, home language/literacy environment, and number of ear infections. The interactions were tested using composite speech, language, and preliteracy phenotypes and previously identified linkage peaks on 6p22 and 15q21. Results showed five G x E at both the 6p22 and 15q21 locations across several phenotypes and environmental measures. Four of the five interactions were consistent with the bioecological model of G x E. Each of these four interactions involved environmental measures of the home language/literacy environment. The only interaction that was consistent with the diathesis-stress model was one involving the number of ear infections as the environmental risk variable. The direction of these interactions and possible interpretations are explored in the discussion.
authors.affiliation: University of Denver, Department of Psychology, Frontier Hall, 2155 S Race Street, Denver, CO 80209, USA. lmcgrath@du.edu
authors.forename: Lauren M
authors.initials: LM
authors.lastname: McGrath
authors.forename: Bruce F
authors.initials: BF
authors.lastname: Pennington
authors.forename: Erik G
authors.initials: EG
authors.lastname: Willcutt
authors.forename: Richard
authors.initials: R
authors.lastname: Boada
authors.forename: Lawrence D
authors.initials: LD
authors.lastname: Shriberg
authors.forename: Shelley D
authors.initials: SD
authors.lastname: Smith
mesh_terms: D001184:Articulation Disorders / Q000235:genetics* / Q000523:psychology; D002648:Child; D002675:Child, Preschool; D002874:Chromosome Mapping; D002896:Chromosomes, Human, Pair 6; D002899:Chromosomes, Human, Pair 9; D004410:Dyslexia / Q000235:genetics / Q000523:psychology; D004522:Educational Status; D005260:Female; D020022:Genetic Predisposition to Disease / Q000235:genetics* / Q000523:psychology; D005838:Genotype; D006801:Humans; D007805:Language Development Disorders / Q000235:genetics* / Q000523:psychology*; D008297:Male; D008957:Models, Genetic; D010641:Phenotype; D010700:Phonetics; D035781:Siblings; D012931:Social Environment; D012959:Socioeconomic Factors; D013065:Speech Intelligibility