Positive association of neuroligin-4 gene with nonspecific mental retardation in the Qinba Mountains Region of China.

Neuroligin-4 is essential for proper brain function. Some studies indicate a close relationship between neuroligin-4 and several human psychiatric conditions. The case-control method was used to study the association between nonspecific mental retardation (NSMR) and genetic variants of neuroligin-4 gene (NLGN4). Five single nucleotide polymorphisms (SNPs: rs5916271, rs7049300, rs6638575, rs3810686, and rs1882260) were genotyped by PCR-RFLP/SSCP method in the NLGN4. Individual SNP analysis shows significant differences at SNPs rs3810686 and rs1882260 for allele frequency when NSMR cases and controls [odds ratio (OR)=1.589, 95% confidence interval (CI)=1.035-2.438, chi2=4.53, df=1, P=0.033; OR=2.050, 95% CI=1.211-3.470, chi2=7.38, df=1, P=0.007, respectively] were compared. Further haplotype analysis indicates that there are two haplotype sets, rs3810686-rs1882260 and rs6638575-rs3810686-rs1882260, which show statistical differences between NSMR cases and controls (chi2=6.79, df=2, global P=0.034; chi2=9.29, df=2, global P=0.0096, respectively). The results suggest a positive association between the genetic variants of the NLGN4 and NSMR in the Chinese children from Qinba Mountains Region.