The Association Study Between The Genes Related With Dopaminergic Transmitters And The Mental Retardation Of Children In QinBa Area

Mental retardation is a human mental disorder with the 1-3% incidence in some of counties and regions among children. The higher incidence will found out in isolated and underdeveloped regions. The Qinba mountain region, which is one of the higher MR prevalence areas in China, has a characteristic of family aggregation and effected by certain genetic factors. So, it is a very important and practical thing that to make clear the genetic pathogeny of MR in Qinba aera.The recent researchs indicated that dopaminergic neurotransmitters including the dopamine, noradrenaline, adrenaline etc, have a close relation with human mental disorders, such as schizophrenia, Alzheimer disease, attention deficit/hyperactivity disorder, bipolar disorder and cognitive ability impairment. And more and more people relized the importance of dopaminergic transmitters' genes for humans' health. Unfortunately, there are few studies about the association between the catechol-O-methyltransferase (COMT) gene, monoamine oxidase isozyme A (MAOA) genes which regulate the dopaminergic neurotransmitters' metabolize levels, and the children mental retardation, the cognitive ability as well.The subjects of this study were collected randomly from 4-16 children of the QinBa region in Shannxi province in northesten Chinese. The case-control method was used. Proper genetic markers, which including the functional markers and non-markers, were genotyped by PCR method and RFLP, VNTR and SSCP methods. The original information and the data of experiment were collected and in-put using the Microsoft Visiual FoxPro 9.0 and SPSS software package. The relationship between the COMT, MAOA genes and MR children in QinBa region were assessed by the single-site and haplotype association analysis.The positive relationship was found out between the polymorphism of COMT gene sequence and the children MR by association analysis with case-controls sample. The significant distribution was displayed between in case and controls children, no matter the compares of the single sites and eight haplotypes combined by rs4646312,rs740603 and rs 165656 markers of COMT. While the positive association between the MR, control children and bordary was found out in the haplotype rs740603-rs165656 (Global p=0.022 & p=0.038) when we shortened the analysis region of COMT by two point haplotype analysis. The rs4680 of COMT, which related with human' schizophrenia, Alzheimer disease, attention deficit/hyperactivity disorder, bipolar disorder and cognitive ability impairment, have no association with mental retardation of children in Qinba region. No any association was found out among MAOA gene and MR in Qinba area.The results of this study indicated that: there was positive association between the COMT gene and the MR in children of Qinba region, and the related functional site which responsed for MR region located nearby the rs740603 and rs165656 region. But further research is needed to determine whether other genetic variants of COMT gene are related to MR outcomes.