Genetic Etiology of Spelling Deficits in the Colorado and London Twin Studies of Reading Disability

DeFries, John C.; Stevenson, Jim; Gillis, Jacquelyn J.; Wadsworth, Sally J.

doi:10.1007/978-94-011-2450-8_6

Cited by 15 publications

(16 citation statements)

References 13 publications

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“…The first report on the heritability (Stevenson, Graham, Fredman, & McLoughlin, 1987) supported a higher heritability for spelling than for reading (.75 when intelligence was controlled). Subsequently DeFries, Stevenson, Gillis, and Wadsworth (1991) reported modest heritability for a test of spelling, again not differentiating lexical and non-lexical processes. Beyond these heritability studies, spelling has also been a phenotype in molecular genetic studies, again often showing more substantial relationship than reading (Grigorenko et al, 2001;Nothen et al, 1999;Petryshen et al, 2001;Schulte-Ko¨rne et al, 1998).…”

Section: Dual Route Genetic Model Of Spellingmentioning

confidence: 98%

Genetic and environmental bases of reading and spelling: A unified genetic dual route model

et al. 2006

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We develop and test a dual-route model of genetic effects on reading aloud and spelling, based on irregular and non-word reading and spelling performance assessed in 1382 monozygotic and dizygotic twins. As in earlier research, most of the variance in reading was due to genetic effects. However, there were three more specific conclusions: the first was that most of the genetic effect is common to both regular and irregular reading. In addition to this common variance evidence was found for distinct genes influencing the acquisition of a lexicon of stored words, and additional genetic effects influencing the acquisition of grapheme-phoneme correspondence rules. The third conclusion, from a combined model of reading and spelling, is that reading and spelling have a common genetic basis. Models that did not distinguish lexical and nonlexical performance fit significantly worse than dual route genetic models. An implication of the research is that models of reading, whether connectionist or dual-route, must allow for the genetic independence of neurological processes underlying the decoding of non-words and irregular words.In this paper we describe and test a model of the genetics of reading that suggests that reading of irregular words and of non-words is influenced by different genes: a genetic extension of the dual route model of reading (Coltheart, Rastle, Perry, Langdon, & Ziegler, 2001). This model is extended to spelling, and, finally, to a joint genetic model of reading and spelling. The predictions of these models are tested using a large adolescent twin sample, and the fit of the genetic dual route model is examined for both reading and spelling. It appears that both the correlation and the differences between lexical and non-lexical reading measures are highly genetic. Subsequently, we test genetic models of reading that do not make a basic distinction between lexical and non-lexical processing and consider the implications of the genetic

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Section: Dual Route Genetic Model Of Spellingmentioning

confidence: 98%

Genetic and environmental bases of reading and spelling: A unified genetic dual route model

et al. 2006

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“…The prevalence rate varies between 5 and 10 percent depending on the chosen diagnostic criteria and sample ascertainment strategies (12). Twin studies of dyslexia have indicated that deficits in spelling are substantially heritable and that the heritability of spelling deficits is higher than the heritability of reading deficits (2,14).…”

mentioning

confidence: 99%

Genetic linkage analysis with dyslexia: Evidence for linkage of spelling disability to chromosome 15

Nöthen

Schulte‐Körne

Grimm

et al. 1999

European Child & Adolescent Psychiatry

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Dyslexia (reading and spelling disability) is one of the most frequently diagnosed disorders in childhood. Twin studies of dyslexia have indicated that deficits in spelling are substantially heritable and that the heritability of spelling deficits is higher than the heritability of reading deficits. We conducted a linkage study for spelling disability in seven multiplex families from Germany. Following previously reported linkage findings of components of dyslexia to chromosome 6p21-p22 and 15q21, we genotyped 26 microsatellite markers covering all of chromosome 6, and 13 microsatellite markers covering all of chromosome 15. While the chromosome 6 data were negative, results from chromosome 15 markers supported a locus on 15q21. The highest two-point LOD score was 1.26 with marker D15S143 at theta = 0. A multipoint LOD score of 1.78 (p = 0.0042) was achieved with a maximum at D15S132. Thus, our results provide independent support for a dyslexia gene on the long arm of chromosome 15.

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“…Estimates of heritability were .62 and .61, respectively, suggesting that genetic factors were associated with more than half the variation in spelling disability (DeFries et al, 1991c). These findings are particularly striking given differences in the test instruments and ascertainment criteria used in the two studies.…”

Section: Twin Studies Of Spelling Disabilitiesmentioning

confidence: 91%

“…This is because normal reading ability may be affected by multiple genes (Vogler & DeFries, 1986), while reading disability may assume varied forms, possibly associated with single genes (Tuckerman et al, 1985). Spelling performance is also of interest to investigators wishing to understand reading and writing difficulties (DeFries et al, 1991c). Several studies of spelling ability and disability have recently appeared in the behavioral-genetic literature.…”

Section: Behavioral-genetic Analyses Of Reading and Spelling Disabilimentioning

confidence: 98%

“…Spelling data provided by selected twin pairs in the Colorado (DeFries et al, 1991c) and British (Stevenson et al, 1987) studies were submitted to the same analytical procedure to compare the degree of genetic influence. Estimates of heritability were .62 and .61, respectively, suggesting that genetic factors were associated with more than half the variation in spelling disability (DeFries et al, 1991c).…”

Section: Twin Studies Of Spelling Disabilitiesmentioning

confidence: 99%

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A Twin Research Perspective on Reading and Spelling Disabilities

Segal

Topoloski

1995

Reading & Writing Quarterly

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Genetic Etiology of Spelling Deficits in the Colorado and London Twin Studies of Reading Disability

Cited by 15 publications

References 13 publications

Genetic and environmental bases of reading and spelling: A unified genetic dual route model

Genetic and environmental bases of reading and spelling: A unified genetic dual route model

Genetic linkage analysis with dyslexia: Evidence for linkage of spelling disability to chromosome 15

A Twin Research Perspective on Reading and Spelling Disabilities

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