The Relative Study Of Parkin Genetic Susceptibility In Chinese Patients With Parkinson's Disease

Despite progress in research on the etiology and pathophysiology of Parkinson's disease, the primary cause of this disease remains unknown now.Most scholar approve that environmental and genetic factors are predispose to PD. Recent research have demonstrated that the overall genectic factors ubiquitous contribute to the pathogenesis of PD, however mutation in the Parkin gene are now known to be responsible for parts of PD, which is the one of the most close genetic susceptibility to PD. Studies have proved that mutation in the Parkin gene have its formulation and relate to different type of PD. So the study of mutation in Parkin gene may play an important role to defining the pathogenesis of Parkinson's disease and to the clinical diagnosis and therapy.OBJECTIVE To study the difference of the genetic susceptibility of exon4 , exon6 and exon7 in Parkin gene between Sporadic Parkinson's disease (SPD) and Familial Parkinson's disease (FPD) byPCR , Gene sequence detection and TDI-FP technique, and research the relativity between stereotactic surgery effect and genetic susceptibility of Parkin gene mutation .To explore the important role of Parkin gene in the pathogenesis of Parkinson's disease, and establish a new method for genotyping of mutation patterns, and seek a new indication for stereotactic surgery.METHODS The experiment group consists of 250 patients of Parkinson's disease, include 36 FPD(family Parkinson's disease) patients and 214 SPD (Sporadic Parkinson's disease) patients. All the experiment group are inpatients in our department from February in 1999 to June in 2004, who accept stereotatic surgery on thalamas, internal pallidum or the subthalamic nucleus (STN). there are 210 patients who had accepted thalamatomy or internal pallidutomy and 40 patients had accepted deep brain stimulation on STN. The control group consists of 250 healthy subjects. There are no significance of differennce in sex and age between the two groups. (1) Genomic DNA was extracted from peripherial whole blood cells according to standard procedures. (2) The extracting of target DNA fragment: Nucleotide sequences of coding exons(exon4, exon6 and exon7) in Parkin gene were amplified by polymerase chain reaction (PCR) and were determined by direct sequencing of PCR products obtained from genomic DNA. the deletion mutation were identified by agarosegel electrophoresis. (3) A mutation type and a wideness type wereestablished by clone and gene sequence detection in the experiment and control groups in which were not be identidied the deletion mutation. (4) The SNP identification of mutation site: accoding to the results of gene sequence detection , applying the TDI-FP(template directed dye-terminator incorporation with fluorescence polarization detection) technique, The FP value of the R110 or TAMRA-labeled ddNTP was detected by TDI-FP assay to determine the SNP mutation genotype, identificate the SNP mutation site of exon4, exon6 and exon7 of Parkin gene in the experiment and control groups which were not be identidied the deletion mutation. (5) UPDRS (Unitified Parkinson Disease Rating Scale) value: we analysed and compared the main symptoms and improvement in UPDRS between pre-operation and one week of post-operation and observe the operation effect between the PD patients who were detected Parkin gene mutation and the patients who were not detected Parkin gene mutation.RESULTS Of the 36 cases with FPD, the exon4 DNA fragment deletion was found in 8 cases and the G→A point gene mutation was found in 2 cases in 601 site; the exon6 DNA fragment deletion was found in 5 cases and the T→C point gene mutation was found in 1 case in 768 site; the exon7 DNA fragment deletion was found in 3 cases and no point gene mutation was found in exon7. Of the 214 cases with SPD, the exon4 DNA fragment deletion was found in only2 cases but the G→A point gene mutation was found in 40 cases in 601 site; the exon6 DNA fragment deletion was found in 2 cases while the T→C point gene mutation was found in 22 case in 768 site and the C→G point gene mutation was found in 20 case in 820 site; the exon7 DNA fragment deletion was found in only 1 case while the C→T point gene mutation was found in 10 cases in 924 site and the G→C point gene mutation was found in 12 cases in 952 site . However, in the control group(250 cases), no target DNA fragment deletion was found , while the G→A point mutation was found in 10 cases of exon4 in 601 site; the T→C point mutation was found in 5 cases of exon6 in 768 site and the C→G point gene mutation was found in 3 cases in 820 site; the C→T point gene mutation was found in 3 cases in 924 site and the G→C point gene mutation was found in 8 cases in 952 site . 118 PD patients who were detected to have the Parkin gene mutation (including deletion mutation and point mutation)were found that their UPDRS improving rate were respectively 57.8% and 68.2% in "on" state and "off' state, which is higher than the PD patients who were not detected to have the Parkin gene mutation and their UPDRS improving rate were respectively 51.2 % and 60.0 % in "on" state and "off" state. CONCLUSION (1) Hereditary factor is one of the key factors in the pathogenesis of Parkinson's disease. There were two different genectic characteristic between Sporadic PD and Familial PD, which...