Association study of the CNS patterning genes and autism in Han Chinese in Taiwan

Autism is a complex neurodevelopmental disorder with high heritability. Despite different approaches worldwide to identify susceptibility loci or genes for autism spectrum disorders (ASDs), no consistent result has been reported. CNS patterning genes have been recognized as candidate genes for autism based on neuroimage and neuropathology evidence. This study investigated four candidate genes (WNT2, EN2, SHANK3, and FOXP2) by a tag SNP approach in a family-based association study. The trio samples include 1164 subjects from 393 families, including 393 probands (aged 9.1 ± 4.0 years; male, 88.6%) diagnosed with autistic disorder (n = 373) or Asperger's disorder (n = 20) according to the DSM-IV diagnostic criteria and confirmed by the Chinese ADI-R interview. Three tag SNPs of EN2 (7q36), 6 SNPs of WNT2 (7q31–33), 5 SNPs of SHANK3 (22q13.3), 3 SNPs of FOXP2 (7q31) were genotyped. TDT analysis was done to test the association of each tag SNP and haplotype. There was no association with autism for 17 tag SNPs of WNT2, EN2, SHANK3, and FOXP2 based on SNP analyses. Haplotype analyses did not reveal significant association except for the 6 tag SNPs of WNT2 gene showing a significant association on one haplotype composed of rs2896218 and rs6950765 (G–G) (p = 0.0095). Other haplotypes composed of rs2896218 and rs6950765 (G–G) were also significantly associated with autism. The present study indicates that SHANK3 may not be a critical gene for the etiology of ASDs in Han Chinese population. Inconsistent findings in EN2 and FOXP2 in the Han Chinese population need further clarification. A haplotype of WNT2 (rs2896218–rs6950765: G–G) is significantly associated with ASDs in our trios samples, this finding warrants further validation by different sample and confirmation by functional study.

Research highlights
► Four candidate genes (WNT2, EN2, SHANK3, and FOXP2) were investigated by a tag SNP approach in a family-based association study.
► TDT analysis revealed no association with autism for the 17 tag SNPs.
► Haplotype analyses did not reveal significant association except for a haplotype of WNT2, composed of rs2896218 and rs6950765.