Association Study Between DRD2 Receptor Gene Polymorphism And Response To Methadone Maintenance Treatment

Objective:To investigate the relationship of DRD2 receptor gene TaqIA and-141C Ins/Del polymorphisms and response to methadone maintenance treatment.Methods:A case-control study was designed by collecting the blood samples of 81 heroin addicts who are Han nationalities in the city of Kunming and have received methadone maintenance treatment.The Polymerase Chain Reaction-Restriction Fragment Length polymorphisms(PCR-RFLP)technique was used to detect the genotype and allele frequencies of DRD2 gene TaqIA and -141C Ins/Del polymorphism.Investigate the clinical characters including the status of the retention,methadone dose used,psychologic status,and craving level of heroin dependence patients to analyze the association of clinical phenotype and genotypes/alleles.Results:1.There are statistical significances in distribution of the genotype of DRD2 gene TaqIA between 0 absence-unit group and over 2 absence-unit group(P=0.002); the frequency of allele A1 is significantly higher in over 2 absence-unit group than in 0 absence-unit group and 1 absence-unit group(P=0.001;P= 0.032).Also,the distribution of the genotype that carry A1(A1/A1+ A1/A2)is significantly higher in over 2 absence-unit group than in 0 absence-unit group and 1 absence-unit group(P=0.008;P=0.03),and that of the genotype which carry A2(A1/A2+A2/A2)is significantly higher in 0 absence-unit group than in over 2 absence-unit group(P=0.002)。2.There are not statistical significances in distribution of the genotype of DRD2 gene-141C Ins/Del among 0 absence-unit group,1 absence-unit group and over 2 absence-unit group(P=0.437;P=0.52;P=0.99).Also,the frequency of allele is not significant among these three groups(P=0.461;P=0.598;P=0.901 The distribution of the genotype that carry Del(Del/Del+Del/Ins)(P=0.215;P =0.291;P=0.944)or that carry Ins(Del/Ins+Ins/Ins)(P=0.984;P=0.896; P=0.893)is not significant among these three groups.3.The average methadone dose of the patients who carry allele A1(A1/A1+ A1/A2)is significantly higher than those who do not carry allele A1(A2/A2) during the period of receiving methadone treatment(P=0.04).There are not statistical significances of the average methadone dose between the patients who carry allele Del(Del/Del+Del/Ins)and those who do not carry allele Del(Ins/Ins) (P=0.571).4.There is statistical significances in the average methadone dose of the patients who are in 0 absence-unit group,1 absence-unit group and over 2 absence-unit group(P=0.016).5.There is not statistical significances in Interpersonal Relationship factor score of SCL-90 between the patients who have received methadone treatment and domestic norm,and the other factor score of SCL-90 of the patients who have received methadone treatment is significantly higher than domestic norm.6.There is not association between DRD2 receptor gene TaqIA and-141C Ins/Del polymorphisms and each factor score of SCL-90 and craving level score in patients who have received methadone treatment for one year.Conclusions:1.DRD2 receptor gene TaqIA polymorphism may be associated with the response to methadone maintenance treatment in heroin addicts who are Han nationalities in the city of Kunming.The patients who carry allele A1 are easier to be absent from the methadone maintenance treatment and to use heroin agin.2.DRD2 receptor gene -141C Ins/Del polymorphism may be not associated with both the response to methadone maintenance treatment in heroin addicts who are Han nationalities in the city of Kunming and the average methadone dose that the patients have received.3.DRD2 receptor gene TaqIA polymorphism may be associated with the average methadone dose that the patients have received.The patients who carry allele A1 may need higher dose of methadone in maintenance treatment.4.The average methadone dose that the patients have received affects the status of the retention of the patients.The higher dose of methadone in maintenance treatment can reduce the absence rate of the patients.5.The function Interpersonal Relationship of the patients who have received methadone treatment for one year has improved,but there are also many psychological problems to be solved.6.There is not association between DRD2 receptor gene TaqIA and -141C Ins/Del polymorphisms and each factor score of SCL-90 and craving level score in patients who have received methadone treatment for one year.