Objective: To explore the relationship between gene polymorphism of GABAA receptors and childhood autism by detecting rs140682, rs2081648 and rs140679 site of single nucleotide polymorphism (SNP) in GABAA receptors gene.
Methods: A total of 94 children with autism and 124 normal children were enrolled in a hospital from November 2010 to May 2011. Childhood autism rating scale (CARS) and autism behavior checklist (ABC) were used to evaluate or investigate the case group. After collecting venous blood and extracting the genome DNA, the allele and genotype of SNP rs140682, rs2081648 and rs140679 site in GABAA receptors gene were detected by PCR-RFLP. The allele and genotype of case group and control group were analyzed by χ(2) test, while the score of scales was analyzed by Spearman rank correlation analysis.
Results: The age of the case group was 5.12 ± 0.32, and it was 5.25 ± 0.27 in the control group (P < 0.05). In case group, the frequency of genotype CC, CT and TT of rs140682 site was 44, 41 and 9, while it was 48, 65, and 11 in control group (P > 0.05), respectively. The frequency of genotype AA, AG and GG of rs2081648 site was 8, 58 and 28 in case group, while it was 12, 49 and 63 in control group (P < 0.05), respectively. In case group, the frequency of genotype CC, CT and TT of rs140679 site was 15, 36 and 43, while it was 18, 59 and 47 in control group (P > 0.05), respectively. It was revealed by Spearman rank correlation analysis that of rs2081648 site, there was a positive correlation between genotype AG and sensation factor (S), social intercourse factor (R), and language factor (L) of autism behavior checklist (ABC) (r values were 0.149, 0.165 and 0.155, all P values < 0.05). A negative correlation between genotype GG and S, R, L and self-help factor (V) was proved (r values were -0.140, -0.173, -0.158 and -0.135, all P values < 0.05). There was a positive correlation between allele A and R and L factors (r values were 0.153 and 0.137, all P values < 0.05), while a negative correlation between allele G and R and L factors (r values were -0.153 and -0.137, all P values < 0.05). In case group, 42 children were diagnosed with mild-to-moderate autism, while 52 children were severe autism. There was no statistically significant correlation between allele or genotype of SNP rs140682 and rs140679 site and the degree of autism (P > 0.05). There was a positive correlation between allele A and genotype AG and the degree of autism (r values were 0.147 and 0.616, all P values < 0.05), while a negative correlation between allele G and genotype GG and the degree of autism (r values were -0.159 and -0.616, all P values < 0.05).
Conclusion: The SNP rs2081648 site which located in GABAA receptors gene may be related to autism. No evidence for significant association between rs140682 and rs140679 site and autism was found.