Association Study Between TRAPPC9 Gene And Mental Retardation In Qin-Ba Mountain-family-based Association Analysisi

Mental retardation (MR), also known as intellectual disability (ID), is mental and neurological disease characterized by cognitive dysfunction and social adaptation deficits. It mainly occurs during development with the incidence of an estimated 1%-3%, which seriously affects people's daily life. The China's central and western region, including SHAN, E, GAN, and YU, is one of the main impoverished regions with the high incidence of MR disease. So it is particularly important to investigate the genetic epidemiology of MR and search the related genes leading to the MR disease of this region.It has confirmed that TRAPPC9 (trafficking protein complex 9) gene is another autosomal recessive gene which can cause MR disease. The coding protein TRAPPC9, called NIBP (IKKb NIK-and IKKb-binding protein), mainly involves in the membrane bubble transport process, and also enhances the activation function of nuclear factor (NF) nuclear kappaB factor-kB (nuclear factor kappaB) induced by TNFa-. The study was to explore the correlation between the TRAPPC9 gene polymorphism and the Han population of Qinba area.Seven single nucleotide polymorphisms (SNPs) marker sites (rs3735803 and rs3735802 located in the exons, rs4736095, rs2233230, rs4736168, rs7010437 and rs2977456 located in the intron) were selected and the genotypes were determined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and PCR-single strand conformation polymorphism (PCR-SSCP) analysis for the above polymorphisms among 176 mental retardation patients and their parents from Qinba mountain area of southern SHANXI province. The correlation between the polymorphism of the gene and mental retardation was investigated by the transmission disequilibrium test (TDT) and haplotype-based association test with the FBAT software. The results showed that the disequilibrium of every allelic gene of the 7 SNPs did not exist in all the families (p>0.05). The linkage disequilibrium (LD) existed in the rs3735802, rs3735803 and rs2977456 (D'>0.8). The further corresponding haplotype analyses were examined in 176 families by haplotype-based association test, revealing the significant difference was also not found between the haplotype and MR (p>0.05 after Bonferroni). The above results indicated the SNPs marks of TRAPPC9 gene did not show association with the MR patients of Qinba mountain region, and also might not be the recessive gene leading to the MR disease of this region.