Genetic analysis of reelin gene (RELN) SNPs:: No association with autism spectrum disorder in the Indian population

Involvement of reelin with Autism spectrum disorder (ASD) has been implicated through several biochemical as well as genetic studies. Reelin is an extracellular signaling protein, which plays a significant role in cytoarchitectonic pattern formation of different brain areas during development. Reelin gene (RELN) is located on chromosome 7q22; an important autism critical region identified through several genome-wide scans. A number of genetic studies have been carried out to investigate the association of reelin with autism. Recently we reported possible paternal effect in the transmission of CGG repeat alleles of RELN in the susceptibility towards autism. Further analysis on other polymorphisms is warranted to validate the status of RELN as a candidate for autism. Therefore in the present study, we have investigated six more SNPs (rs727531, rs2072403, rs2072402, rs362691, rs362719, rs736707) in 102 patients, 182 parents and 101 healthy controls. We have followed DSM-IV criteria and the screening for autism was carried out using CARS. Genomic DNA isolated from blood was used for PCR and subsequent RFLP analysis. Finally, case-control and family-based association studies were carried out to examine the genetic association of these SNP markers with ASD in the Indian population. But, we failed to detect either preferential parental transmission of any alleles of the markers to affected offspring or any biased allelic or genotypic distribution between the cases and controls. Thus the present study suggests that these SNPs of RELN are unlikely to be associated with ASO in the Indian population. (C) 2008 Elsevier Ireland Ltd. All rights reserved.