Research On Clinical Assessment, Biochemical Markers And Mitochondrial DNA Mutation Analysis Of Patients With SCA3/MJD

Chapter1:Research on Clinical Assessment of Patients with SCA3/MJDObjective:To investigate the related factors of International cooperative ataxia rating scale and scale for the assessment and rating of ataxia scores on SCA3/MJD patients.Methods:One hundred and twenty-six patients with genetically determined SCA3/MJD were assessed by ICARS and SARA. The relation between ICARS or SARA scores and age of onset, disease duration and expanded CAG repeat number of MJD1gene were statistically analysed.Results:Either the total ICARS or the total SARA score was positively related with disease duration (r=0.586, P<0.05; r=0.643, P <0.05). Simple linear regression equations were Y1(total ICARS score)=13.072+2.388X2(disease duration)(F=68.874, P<0.05) and Y2(total SARA score)=4.403+0.961X2(disease duration)(F=87.254,P<0.05). Either age adjusted the total ICARS score or age adjusted the total SARA score was positively related with CAG repeat size (r=0.328,P<0.05; r=0.335, P<0.05). Both the ICARS subscores and the SARA subscores were positively related with disease duration (r=0.257～0.589, P<0.05; r=0.432-0.623, P<0.05). Both age adjusted ICARS subscores and age adjusted SARA subscores were positively related with CAG repeat size (r=0.263-0.403, P<0.05; r=0.189～0.366, P<0.05). Analysis of variance showed that the total ICARS score and the total SARA score increased with the disease stage.Conclusion:ICARS and SARA are reliable and effective scales for assessing the severity of ataxia in patients with SCA3/MJD. The investigator can choose the best suitable scale according to requirement. Chapter2:Study on the biochemical markers of the SCA3/MJD PatientsObjective:The aim of the study was the assessment of neuron-specific enolase (NSE), protein S100B(S100B), insulin-like growth factor-1(IGF-Ⅰ) and insulin-like growth factor binding protein-3(IGFBP-3) serum concentrations and to evaluate the potential use of NSE, S100B, IGF-Ⅰ and IGFBP-3serum concentrations as biochemical markers in SCA3/MJD patients.Methods:Serum concentrations of NSE, S100B, IGF-I and IGFBP-3were measured in one hundred and two SCA3/MJD patients and compared with100healthy subjects matched by sex and age. The correlations between these biochemical markers and age, age of onset, disease duration, CAG repeat size, the scores of International cooperative ataxia rating scale(ICARS), and Scale for the assessment and rating of ataxia(SARA) were also assessed.Results:Compared with healthy controls, patients with SCA3/MJD demonstrated higher NSE serum concentrations (6.95ng/mL vs4.83ng/mL, P<0.05) and higher S100B serum concentrations (0.07ng/mL vs0.05ng/mL,P<0.05), and patients with SCA3/MJD demonstrated lower IGF-I serum concentrations (90.99ng/mL vs100.00ng/mL,P<0.05) and lower IGFBP-3serum concentrations (2314.66ng/mL vs2659.27ng/mL, P<0.05), but there were no differences in the IGF-I:IGFBP-3molar ratio. In SCA3/MJD patients group, NSE levels presented a positive correlation with age, disease duration, ICARS scores and SARA scores, whereas S100B levels did not correlate with age, age of onset, disease duration, ICARS scores and SARA scores, but IGF-I levels, IGFBP-3levels, and the IGF-I:IGFBP-3molar ratio showed no relation to clinical and molecular parameters. CAG repeat size did not correlate with NSE levels and S100B levels in different age groups of SCA3/MJD patients. Conclusions:it seems that serum NSE might be a useful marker to monitor disease progression and represent the degree of severity of this disease, and elevated S100B serum concentrations in patients compared to healthy controls may suggest an application of this protein as a peripheral marker of brain impairment in SCA3/MJD. Serum IGF-I and IGFBP-3can not be useful biochemical markers in SCA3/MJD. Chapter3:Research on Mitochondrial DNA Mutation of Patients with SCA3/MJDObjective:To discuss the mtDNA mutations of SCA3/MJD patients, this might provide clues to reveal the role of mtDNA in SCA3/MJD pathogenesis.Methods:screening for micro-mutations of MT-LT1, MT-ND1, MT-COII, MT-TK, MT-ATP8, and MT-ATP6genes was carried out by PCR and direct sequencing technologies and relative mtDNA copy number was measured using real-time PCR in102patients with genetically determined SCA3/MJD and100healthy controls. Results:In SCA3/MJD patients group,24sequence variations were found by micro-mutation detection of mtDNA genes, and in healthy controls10sequence variations were found group, and in which variations T8872C was found in both groups. There were no differences between SCA3/MJD patients and healthy controls in the relative mtDNA copy number (93.20vs89.66, P>0.05). In SCA3/MJD patients group, relative mtDNA copy number presented a negative correlation with the number of CAG repeat (r=-0.210, P<0.05), but did not correlate with age, age of onset, disease duration, ICARS scores and SARA scores.Conclusion:SCA3/MJD patients showed high levels of mtDNA variations, we suggest that there were no differences between SCA3/MJD patients and healthy controls in the relative mtDNA copy number and it may not serve as a biomarker of the severity of SCA3/MJD.