{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,4]],"date-time":"2026-05-04T11:03:08Z","timestamp":1777892588391,"version":"3.51.4"},"reference-count":33,"publisher":"SAGE Publications","issue":"2","license":[{"start":{"date-parts":[[2000,3,1]],"date-time":"2000-03-01T00:00:00Z","timestamp":951868800000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/journals.sagepub.com\/page\/policies\/text-and-data-mining-license"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["J Learn Disabil"],"published-print":{"date-parts":[[2000,3]]},"abstract":"<jats:p>\n                    To test the hypothesis that the genetic etiology of reading disability differs as a function of IQ, composite reading performance data from 223 pairs of identical twins and 169 pairs of same-gender fraternal twins in which at least one member of each pair was classified with reading disability were subjected to multiple regression analysis (DeFries &amp; Fulker, 1985, 1988). In the total sample, heritability of the group deficit in reading performance ( h\n                    <jats:sup>2<\/jats:sup>\n                    <jats:sub>g<\/jats:sub>\n                    ) was .58 (\u00b1 .08). However, when the basic regression model was fitted separately to data from twin pairs with average Wechsler (1974, 1981) full scale IQ scores below 100 or 100 and above, resulting estimates of h\n                    <jats:sup>2<\/jats:sup>\n                    <jats:sub>g<\/jats:sub>\n                    were .43 and .72, respectively, a significant difference ( p \u2264 .03, one-tailed). The results of fitting extended regression models to reading performance and continuous IQ data provide evidence that the genetic etiology of reading disability differs as a linear function of IQ ( p \u2264 .007, one-tailed). These results suggest that IQ is relevant for the diagnosis of reading disability and that environmental influences may be more salient as a cause of reading difficulties in children with lower IQ scores.\n                  <\/jats:p>","DOI":"10.1177\/002221940003300207","type":"journal-article","created":{"date-parts":[[2007,12,14]],"date-time":"2007-12-14T00:52:20Z","timestamp":1197593540000},"page":"192-199","source":"Crossref","is-referenced-by-count":69,"title":["Differential Genetic Etiology of Reading Disability as a Function of IQ"],"prefix":"10.1177","volume":"33","author":[{"given":"Sally J.","family":"Wadsworth","sequence":"first","affiliation":[{"name":"Institute for Behavioral Genetics, Campus Box 447, University of Colorado, Boulder, CO 80309"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Richard K.","family":"Olson","sequence":"additional","affiliation":[{"name":"Institute for Behavioral Genetics, University of Colorado, Boulder"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Bruce F.","family":"Pennington","sequence":"additional","affiliation":[{"name":"University of Denver, Developmental Neuropsychology Center"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"John C.","family":"DeFries","sequence":"additional","affiliation":[{"name":"Institute for Behavioral Genetics, University of Colorado, Boulder"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"179","published-online":{"date-parts":[[2000,3,1]]},"reference":[{"key":"atypb1","doi-asserted-by":"publisher","DOI":"10.1007\/BF01065975"},{"key":"atypb2","doi-asserted-by":"publisher","DOI":"10.1007\/BF01066994"},{"key":"atypb3","volume-title":"The dyslexic child","author":"Critchley, M.","year":"1970"},{"key":"atypb4","unstructured":"DeFries, J.C. (1985). Colorado reading project. In D. B. Gray & J. F. Kavanagh (Eds.), Biobehavioral measures of dyslexia (pp. 107-122). Parkton, MD: York Press."},{"key":"atypb5","doi-asserted-by":"publisher","DOI":"10.1002\/(SICI)1098-2779(1996)2:1<39::AID-MRDD7>3.0.CO;2-S"},{"key":"atypb6","first-page":"7","volume":"8","author":"DeFries, J.C.","year":"1997","journal-title":"Learning Disabilities: A Multidisciplinary Journal"},{"key":"atypb7","doi-asserted-by":"publisher","DOI":"10.1007\/BF01066239"},{"key":"atypb8","doi-asserted-by":"publisher","DOI":"10.1017\/S0001566000003810"},{"key":"atypb9","unstructured":"DeFries, J.C. & Gillis, J.J. (1991). Etiology of reading deficits in learning disabilities: Quantitative genetic analysis. In J. E. Obrzut & G. W. Hynd (Eds.), Neuropsychological foundations of learning disabilities: A handbook of issues, methods, and practice (pp. 29-47). Orlando, FL: Academic Press."},{"key":"atypb10","unstructured":"DeFries, J.C. & Light, J.G. (1996). Twin studies of reading disability. In J. H. Beitchman, N. J. Cohen, M. M. Konstantareas, & R. Tannock (Eds.), Language, learning, and behavior disorders: Developmental, biological, and clinical perspectives (pp. 272-292). New York: Cambridge University Press."},{"key":"atypb11","volume-title":"Colorado Reading Project: An update","author":"DeFries, J.C.","year":"1991"},{"key":"atypb12","doi-asserted-by":"publisher","DOI":"10.1007\/BF01065564"},{"key":"atypb13","volume-title":"Examiner's manual: Peabody Individual Achievement Test","author":"Dunn, L.M.","year":"1970"},{"key":"atypb14","doi-asserted-by":"publisher","DOI":"10.1037\/0033-2909.101.2.171"},{"key":"atypb15","doi-asserted-by":"publisher","DOI":"10.1037\/h0076502"},{"key":"atypb16","doi-asserted-by":"publisher","DOI":"10.1177\/002221948902200811"},{"key":"atypb17","first-page":"3","volume":"45","author":"Lyon, G.R.","year":"1995","journal-title":"Annals of Dyslexia"},{"key":"atypb18","doi-asserted-by":"publisher","DOI":"10.1177\/002221949803100401"},{"key":"atypb19","first-page":"265","volume":"16","author":"Nichols, R.C.","year":"1966","journal-title":"Acta Genetica"},{"key":"atypb20","volume-title":"A behavioral-genetic analysis of reading disabilities and component processes","author":"Olson, R.K."},{"key":"atypb21","unstructured":"Olson, R.K., Rack, J.P., Conners, F.A., DeFries, J.C. & Fulker, D.W. (1991). Genetic etiology of individual differences in reading disability. In L. V. Feagans, E. J. Short, & L. J. Meltzer (Eds.), Subtypes of learning disabilities: Theoretical perspectives and research (pp. 113-135). Hillsdale, NJ: Erlbaum."},{"key":"atypb22","doi-asserted-by":"publisher","DOI":"10.1177\/002221949202500904"},{"key":"atypb23","doi-asserted-by":"publisher","DOI":"10.1111\/j.1469-7610.1975.tb01269.x"},{"key":"atypb24","first-page":"1","volume":"9","author":"Shaywitz, S.E.","year":"1994","journal-title":"Journal of Special Education"},{"key":"atypb25","doi-asserted-by":"publisher","DOI":"10.1177\/002221948902200803"},{"key":"atypb26","unstructured":"Siegel, L.S. (1998). The discrepancy formula: Its use and abuse. In B. K. Shapiro, P. J. Accardo, & A. J. Capute (Eds.), Specific reading disability: A view of the spectrum (pp. 123-135). Timonium, MD: York Press."},{"key":"atypb27","unstructured":"Stanovich, K. (1986). Cognitive processes and the reading problems of learning-disabled children: Evaluating the assumption of specificity. In J. K. Torgesen & B. Y. L. Wong (Eds.), Psychological and educational perspectives on learning disabilities (pp. 87-131). Orlando, FL: Academic Press."},{"key":"atypb28","doi-asserted-by":"publisher","DOI":"10.1037\/0022-0663.86.1.24"},{"key":"atypb29","doi-asserted-by":"publisher","DOI":"10.1111\/j.1469-7610.1993.tb01779.x"},{"key":"atypb30","doi-asserted-by":"publisher","DOI":"10.1007\/BF01067433"},{"key":"atypb31","volume-title":"Examiner's manual: Wechsler Intelligence Scale for Children-Revised","author":"Wechsler, D.","year":"1974"},{"key":"atypb32","volume-title":"Examiner's manual: Wechsler Adult Intelligence Scale-Revised","author":"Wechsler, D.","year":"1981"},{"key":"atypb33","doi-asserted-by":"publisher","DOI":"10.1177\/002221948902200815"}],"container-title":["Journal of Learning Disabilities"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/journals.sagepub.com\/doi\/pdf\/10.1177\/002221940003300207","content-type":"application\/pdf","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/journals.sagepub.com\/doi\/pdf\/10.1177\/002221940003300207","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,5,1]],"date-time":"2026-05-01T06:33:02Z","timestamp":1777617182000},"score":1,"resource":{"primary":{"URL":"https:\/\/journals.sagepub.com\/doi\/10.1177\/002221940003300207"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2000,3]]},"references-count":33,"journal-issue":{"issue":"2","published-print":{"date-parts":[[2000,3]]}},"alternative-id":["10.1177\/002221940003300207"],"URL":"https:\/\/doi.org\/10.1177\/002221940003300207","relation":{},"ISSN":["0022-2194","1538-4780"],"issn-type":[{"value":"0022-2194","type":"print"},{"value":"1538-4780","type":"electronic"}],"subject":[],"published":{"date-parts":[[2000,3]]}}}