Association Study of Neurexin 1 and Neuroligin 3 & 4 Genes with French Autistic Patients

Background: Beta-neurexin and neuroligin molecules form an intercellular adhesion complex sufficient to trigger formation of functional presynaptic elements. Mutations and copy number variants have been identified in neurexin 1 (NRXN1) and neuroligins 3 & 4 (NLGN3 & NLGN4) genes in autistic patients.

Objectives: Our goal is to identify association between autism and polymorphisms of NRXN1, NLGN3 and NLGN4 genes.

Methods: We performed a case-control study by genotyping 9 single nucleotide polymorphisms (SNPs) within NRXN1, NLGN3 and NLGN4 genes, using TaqMan® SNP Genotyping Assays, on 84 French autistic patients, 26 parents, and 143 healthy controls matching for the geographic origin. Distributions of alleles and genotypes were compared between patients and controls. Transmission disequilibrium test was carried out in families.

Results: SNPs were on Hardy-Weinberg equilibrium. No significant differences of frequency for alleles or genotypes were found between autistic patients and controls. In particular, no variation was observed for the missense mutation R451C in the NLGN3 gene. No excess of transmission was showed from parents to patients.

Conclusions: No association between polymorphisms in NRXN1, NLGN3 and NLGN4 genes was identified with autism in this study.