High Heritability of Speech and Language Impairments in 6-year-old Twins Demonstrated Using Parent and Teacher Report

Abstract

Previous twin studies have demonstrated high heritability of specific language impairment (SLI) when the diagnosis is based on psychometric testing. The current study measured the effectiveness of parent and teacher ratings of communication skills in identifying heritable language impairment. The Children's Communication Checklist was completed by parents and teachers of 6-year-old twins recruited from a general population sample. One hundred and thirty twin pairs (65 MZ) were selected because at least one twin had low language skills at 4 years of age; a further 66 pairs (37 MZ) were a low risk group with no indication of language difficulties at 4 years. Internal consistency, inter-rater reliability, and validity in identifying language impairment were assessed for all CCC scales. CCC scales, especially those assessing structural language skills, were highly effective in identifying cases of language impairment, but agreement between parent and teacher ratings was modest. Genetic analysis revealed negligible environmental influence and substantial genetic influence on most scales. A rater-specific effects model was fit to the data to assess how far parents and teachers assess a common genetic factor on the CCC. Ratings of parents and teachers were influenced to some extent by the same child characteristics, but rater-specific effects were also evident, especially on scales measuring pragmatic aspects of communication. This study shows that there are strong genetic influences on both structural and pragmatic language impairments in children, and these can be detected using a simple checklist completed by parents or teachers.

Exome Sequencing in an Admixed Isolated Population Indicates NFXL1 Variants Confer a Risk for Specific Language Impairment

“…The disorder is highly heritable [5] but genetic contributions are expected to be complex in nature with significant heterogeneity between individuals [6]. Common risk variants within ATP2C2 (OMIM#613082), CMIP (OMIM#610112) [7], ABCC13 (OMIM#608835) [8], FLNC (OMIM#102565), RBFOX2 (OMIM#612149) [9] and ROBO2 (OMIM#602431) [10] have been associated with quantitative measures of language skills.…”

Preconception and Prenatal Environmental Factors Associated with Communication Impairments in 9 Year Old Children Using an Exposome-Wide Approach

“…Language impairments can include those involving semantics, such as subtle nuances, as well as pragmatic aspects of language in a social context [1]. Twin studies have suggested that, although children must be exposed to language in their environment in order to learn it, communication impairments have a major heredity component [2,3]. However, the low estimates of environmental influences may be misleading for two reasons.…”

Does IQ influence Associations between ADHD Symptoms and other Cognitive Functions in young Preschoolers?

“…Teacher reports of language skills would be particularly useful as the informants usually have a large “reference base” for comparison, from years of experience with children of the same age, representing the full range of language skills. Teacher reports provide information about language skills that may be challenging to elicit in a test situation with young preschoolers due to shyness and/or limited motivation or attention [13] and they are easy and inexpensive to administer.…”