Background: Genetic association studies on populations of European origin have identified the DCDC2 gene as a susceptibility locus for developmental dyslexia. Here, we sought to investigate the association of DCDC2 polymorphisms with developmental dyslexia in children of Han Chinese origin.
Methods: We undertook a case-control genetic association study on 76 dyslexic children and 79 non-dyslexic matched controls. We isolated DNA from oral mucosal cell samples and genotyped two DCDC2 coding-sequence single nucleotide polymorphisms, rs2274305 and rs6456593, in each sample using SNaPshot single nucleotide extension. We compared the allele and genotype frequencies between the groups using the χ(2) test and analyzed the relationship between dyslexia and the polymorphism at both loci using unconditional logistic regression. We also predicted haplotypes and compared their frequencies between the two groups.
Results: The differences in the genotype distribution and the allelic genes of the two single nucleotide luci of the DCDC2 gene, rs2274305 and rs6456593, between the two dyslexic and non-dyslexic groups were statistically meaningless (P > 0.05). The differences in the haplotype distributions of the DCDC2 gene between the dyslexic and normal group were statistically meaningless (P > 0.05).
Conclusion: The DCDC2 gene may not be a susceptibility factor for developmental dyslexia among the Han Chinese. However, methodological issues may have prevented the detection of positive associations.