Robinson Crusoe Island is a geographically and socially isolated settlement located over 600km west of the Port of Valparíso, Chile. An unusually high incidence (30%) of the Chilean equivalent of developmental language disorder (TEL) has been reported in Islander children, with 90% of these affected children found to be direct descendants of a pair of original founder-brothers, therefore strongly suggesting a shared genetic basis. Here we utilise whole-genome sequencing to investigate potential underlying variants in a panel of thirty-four genes known to play a role in language disorders, in seven TEL affected and ten unaffected islanders. We use this targeted approach to look for rare, shared variants that may underlie the diagnosis of TEL in a Mendelian genetic model. We go on to test whether the overall burden of rare variants is enriched in individuals affected by TEL or with Islanders related to the founder-brother lineage. In the absence of explanatory rare variants, we further investigate these candidate genes within a complex model of inheritance, where inheriting a small number of moderate impact common variants may increase susceptibility of developing TEL. We examine if any variants segregate with affection status or with founder-brother-related status, and therefore may increase risk of developing a language disorder. Finally, we perform a pooled, gene-based tests to evaluate relationships between combined variation across candidate genes and TEL affection status. Here we report a comprehensive examination of genes directly implicated in language-related mechanisms to identify ‘low hanging fruit’ of causative monogenic Mendelian variants, and complex association model of increased susceptibility in developmental language disorder found on Robinson Crusoe Island.
Mountford, Hayley S.Villanueva, PíaFernández, María AngélicaDe Barbieri, ZulemaCazier, Jean-BaptisteNewbury, Dianne F.
Faculty of Health and Life Sciences\Department of Biological and Medical Sciences
Year of publication: 2019Date of RADAR deposit: 2019-03-26
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