There is considerable variability in the extent to which young people with developmental language disorder (DLD) experience mental health difficulties. What drives these individual differences remains unclear. In the current article, data from the Twin Early Development Study were used to investigate the genetic and environmental influences on…

The authors examined whether math fluency was independent from untimed math and from reading using 314 pairs of school-aged twins drawn from the Western Reserve Reading and Math Projects. Twins were assessed through a 90-min home visit at approximately age 10 and were reassessed in their homes approximately 1 year later. Results suggested that the…

This study investigated the role of the myelin oligodendrocye glycoportein (MOG) gene to reading disability in 22 children with dyslexia and 96 random controls. Results suggest that, although alleles in the MOG gene may be in linkage disequilibrium with a locus that contributes to reading disability, the MOG gene itself is probably not involved.…

This introductory article briefly describes each of the following eight articles in this special issue on the neurology and genetics of learning related disorders. It notes the greater appreciation of learning disability as a set of complex disorders with broad and intricate neurological bases and of the large individual differences in how these…

Examination of methodological issues in the design and interpretation of studies on the genetics of reading disability suggests three tests of increasing rigor for determining whether reading score distributions are categorical and thus not subject to analyses which assume a continuous normal distribution. Also noted are interactive relationships…

Siblings and parents of 39 children with dyscalculia were assessed for arithmetic, reading, and attention disorders. Findings indicated a familial prevalence of dyscalculia almost tenfold higher than expected for the general population and suggest that dyscalculia, like other learning disabilities, has a significant familial aggregation,…

This study examined 87 pedigrees of individuals with histories of preschool phonology disorders. Significantly more family members with dyslexia and learning disabilities, but not stuttering or hearing impairment, were found in pedigrees of individuals with phonology disorders than in pedigrees of nondisabled individuals. (Author/JDD)

Composite reading performance data from 223 pairs of identical twins and 169 same-gender fraternal twins in which at least one member was classified with reading disability were subjected to multiple regression analysis. Results indicated that the genetic etiology of reading disability differs as a linear function of IQ. (Contains extensive…