No Association Between Single Nucleotide Polymorphisms in Distal-Less Homeobox-6 (DLX6) and Autism Spectrum Disorders (ASD) from the Korean Male Population

OBJECTIVES: Autism spectrum disorder (ASD) is a neurodevelopmental disorder that is characterized by abnormalities of social functioning, communication and behavior. The association of the 7q21-34 region with ASD has been reported. The DLX6 gene, which is located at the 7q22 region, is one of the positional and functional candidate genes for ASD. We found that there is no association between DLX6 polymorphisms and ASD in the Korean male population. METHODS: We selected three single nucleotide polymorphisms (SNPs) that might be implicated in the change of the DLX6 gene expression. The genomic DNA was collected from the venous blood of 147 male controls and 179 male patients with ASD. The genotypes of the selected SNPs were determined using the Illumina GoldenGate assay, and the statistical analyses were performed using HapAnalyzer software and SAS Enterprise. RESULTS: We found no association of the three SNPs in the DLX6 gene with ASD in the Korean male population. CONCLUSION: Our study suggests that the three SNPs in the DLX6 gene are not associated with ASD, and we need to analyze the previously reported regions for their associations with ASD.

Characterization of Single Nucleotide Polymorphisms in 55 Disease-Associated Genes in a Korean Population

Most common diseases are caused by multiple genetic and environmental factors. Among the genetic factors, single nucleotide polymorphisms (SNPs) are common DNA sequence variations in individuals and can serve as important genetic markers. Recently, investigations of gene-based and whole genome-based SNPs have been applied to association studies for marker discovery. However, SNPs are so population-specific that the association needs to be verified. Fifty-five genes and 384 SNPs were selected based on association with disease. Genotypes of 337 SNPs in candidate genes were determined using Illumina Sentrix Array Matrix (SAM) chips by an allelespecific extension method in 364 unrelated Korean individuals. Allelic frequencies of SNPs were compared with those of other populations obtained from the International HapMap database. Minor allele frequencies, linkage disequilibrium blocks, tagSNPs, and haplotypes of functional candidate SNPs in 55 genetic disease-associated genes were provided. Our data may provide useful information for the selection of genetic markers for genebased genetic disease-association studies of the Korean population.