DYX1C1 has been identified as a susceptible candidate gene for developmental dyslexia (DD); studies in various populations have yielded inconclusive results and the causal allele is unknown in the Indian population. On the basis of the initial association studies and the role of DYX1C1 in neuronal migration, we investigated the role of DYX1C1 in causing DD in an Indian population.
Ten single-nucleotide polymorphisms (SNPs) of DYX1C1 were genotyped in 210 cases with DD and 256 age-matched nondyslexic controls. Genotyping of these SNPs was carried with the MassARRAY technique using SpectroCHIP and analysed with MALDI-TOF MS. Single-marker and two-marker haplotype analyses were carried out and the χ 2-test, odds ratios, 95% confidence intervals and Yates correction were applied to identify the significance of the genotyped SNPs.
A significant association was observed for the homozygous genotype (GG) of the SNP rs12899331 (3.12%) and individual allele frequency (P=0.039). Psycholinguistic tests showed an association between rs12899331 with dyslexic phenotypes such as word and nonword reading, syllable reversal task, spoonerism task and spelling. Two-marker haplotype analysis also showed a significant association for the markers G/C at rs12899331/rs1075938 (P=0.039) with the phenotypes rapid naming ability and phonological awareness, as well as with word reading, spelling and sentence repetition.
The promoter SNP rs12899331 of DYX1C1 may contribute towards the manifestation of DD. This study supports the association of DYX1C1 with DD in an Indian population.
aGenetics and Genomics Laboratory, Department of Studies in Zoology
bDepartment of Studies in Psychology, University of Mysore, Manasagangotri, Mysore, Karnataka
Correspondence to Nallur B. Ramachandra, PhD, Genetics and Genomics Laboratory, Department of Studies in Zoology, University of Mysore, Mysore 06, Karnataka, India Tel: +91 821 2419781/2419888; fax: +91 821 2516056; e-mail: firstname.lastname@example.org
Received October 26, 2012
Accepted April 8, 2013