Association of DCDC2 Polymorphisms with Normal Variations in Reading Abilities in a Chinese Population.

Yuping Zhang,Twila Tardif,Catherine Mcbride,Hua Shu,Margit Burmeister,Jun Li,Sandra M Villafuerte,Shuang Song,Mengmeng Su

doi:10.1371/journal.pone.0153603

Abstract

The doublecortin domain-containing 2 (DCDC2) gene, which is located on chromosome 6p22.1, has been widely suggested to be a candidate gene for dyslexia, but its role in typical reading development over time remains to be clarified. In the present study, we explored the role of DCDC2 in contributing to the individual differences in reading development from ages 6 to 11 years by analysing data from 284 unrelated children who were participating in the Chinese Longitudinal Study of Reading Development (CLSRD). The associations of eight single nucleotide polymorphisms (SNPs) in DCDC2 with the latent intercept and slope of children’s reading scores were examined in the first step. There was significant support for an association of rs807724 with the intercept for the reading comprehension measure of reading fluency, and the minor “G” allele was associated with poor reading performance. Next, we further tested the rs807724 SNP in association with the reading ability at each tested time and revealed that, in addition to significant associations with the two main reading measures (reading fluency and Chinese character reading) over multiple testing occasions, this SNP also showed associations with reading-related cognitive skills, including morphological production, orthographic judgment and phonological processing skills (rapid number naming, phoneme deletion, and tone detection). This study provides support for DCDC2 as a risk gene for reading disability and suggests that this gene is also operative for typical reading development in the Han population.

Highlights

Developmental dyslexia, or reading disability, is one of the most common neurobehavioral disorders and is characterized by impairments in learning to read, despite normal intelligence and adequate educational opportunities [1]
We tested the association of eight single nucleotide polymorphisms (SNPs) spanning doublecortin domain-containing protein 2 (DCDC2) with reading development in a sample of Chinese children who were followed from 6 to 11 years old
One SNP, rs807724, was found to influence the initial level of children’s reading growth, with the minor “G” allele associated with poor reading performance

Summary

Introduction

Developmental dyslexia, or reading disability, is one of the most common neurobehavioral disorders and is characterized by impairments in learning to read, despite normal intelligence and adequate educational opportunities [1]. Another study [10] tested 147 SNPs in a sample of 153 dyslexic families from Colorado and reported a nominal significance for 37 SNPs, 11 of which were located in DCDC2. DCDC2 has been reported to contribute to reading abilities in the general population [9, 16, 17]. Scerri et al [17] suggested that DCDC2 was associated with reading-related traits in a large general sample (n = 3,725) from southwest England. It yielded significant results in further analyses for dyslexia. The above findings supported the notion that DCDC2 plays an important role in reading ability and/or disabilities

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Conclusion