Investigation of Dyslexia and SLI Risk Variants in Reading- and Language-Impaired Subjects

TLDR

Dyslexia and specific language impairment are common childhood disorders with overlapping symptoms and suspected shared genetic causes, and recent identification of risk variants for both disorders allows direct assessment of their genetic overlap. In this study we investigate the role of variants in genes MRPL19/C20RF3, ROBO1, DCDC2, KIAA0319, DYX1C1, CNTNAP2, ATP2C2, and CMIP in the etiology of SLI and dyslexia. We performed case–control and quantitative association analyses using oral and written language measures in samples of SLI and dyslexic families and cases. We replicated the association of KIAA0319 and DCDC2 with dyslexia, found KIAA0319 also influences oral language ability, and identified associations between reading‑related measures and CNTNAP2 and CMIP variants in SLI families.

Abstract

Dyslexia (or reading disability) and specific language impairment (or SLI) are common childhood disorders that show considerable co-morbidity and diagnostic overlaps and have been suggested to share some genetic aetiology. Recently, genetic risk variants have been identified for SLI and dyslexia enabling the direct evaluation of possible shared genetic influences between these disorders. In this study we investigate the role of variants in these genes (namely MRPL19/C20RF3, ROBO1, DCDC2, KIAA0319, DYX1C1, CNTNAP2, ATP2C2 and CMIP) in the aetiology of SLI and dyslexia. We perform case–control and quantitative association analyses using measures of oral and written language skills in samples of SLI and dyslexic families and cases. We replicate association between KIAA0319 and DCDC2 and dyslexia and provide evidence to support a role for KIAA0319 in oral language ability. In addition, we find association between reading-related measures and variants in CNTNAP2 and CMIP in the SLI families.