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A Twin Study of Mathematics Disability.
Peer reviewed Peer reviewed
Alarcon, Marciela; DeFries, John C.; Light, Jacquelyn Gillis; Pennington, Bruce F. – Journal of Learning Disabilities, 1997
Comparison of twins (40 identical and 23 fraternal) for mathematics deficits (MD), in which at least one member had a mathematics disability, found evidence for a significant genetic etiology. However, tests for the differential etiology of MD as a function of reading performance level were nonsignificant. (Author/DB)
Descriptors: Etiology, Genetics, Heredity, Incidence
Specific Deficits in Component Reading and Language Skills: Genetic and Environmental Influences.
Peer reviewed Peer reviewed
Olson, Richard; And Others – Journal of Learning Disabilities, 1989
Word recognition data from identical and fraternal twins and siblings (N=172) indicated that the phonological coding deficit of children with reading disabilities was highly heritable. Orthographic coding was not significantly heritable. Poor readers with low IQs were superior to similar reading but average IQ readers in phonological coding.…
Descriptors: Elementary Secondary Education, Genetics, Heredity, Intelligence Differences
The External Validity of Age-versus IQ-Discrepancy Definitions of Reading Disability: Lessons from a Twin Study.
Peer reviewed Peer reviewed
Pennington, Bruce F.; And Others – Journal of Learning Disabilities, 1992
This study of 640 twins with reading disability and 436 controls (mean age 12) examined external validity of the distinction between specific reading retardation and reading backwardness, in 3 domains: genetic etiology, sex ratio and clinical correlates, and neuropsychological profiles. There was no evidence of differential genetic etiology of the…
Descriptors: Age Differences, Definitions, Educational Diagnosis, Elementary Secondary Education