【学位级别】医学博士

【论文完成日期】2004-05-08

【论文中文题名】人类FZD3基因和FGF家族基因单核苷酸多态性与精神分裂症的关联研究

【论文外文题名】The Association Study between Human FZD3, FGF Family Genes and Schizophrenia in Chinese Han Population

【论文著者】姓名：张彦波 zhang yan bo

【论文著者】学号：B10199768

【论文著者】系别：精神卫生研究所

【论文著者】专业：精神病与精神卫生学

【论文著者】研究方向：精神分子遗传学

【指导教师】姓名：张岱 zhang dai

【指导教师】学校：北京大学医学部

【指导教师】系别：精神卫生研究所

【指导教师】专业：精神病与精神卫生学

【中文文摘】目的 精神分裂症是人类最常见的重性精神疾病之一，不仅给家庭和社会带来沉重的经济负担，而且还严重威胁社会的安全与稳定；确定其病因从而达到防治是医学界乃至整个社会需迫切解决的问题。遗传流行病学研究证实，精神分裂症与遗传因素有密切关系，但不符合经典的孟德尔单基因遗传规律，属于多基因遗传病或人类复杂疾病。目前的研究已经发现一些与精神分裂症存在关联的染色体区域，这些区域包括染色体1q21-22，6p21，8p21，13q14-32，22q11-13等。 本研究工作以中国北方汉族精神分裂症患者和正常对照为研究对象，对位于人类8号染色体短臂二区一带(8p21)的FZD3，FGF17，FGF20等三个基因的单核苷酸多态性(SNPs)进行分析，并与精神分裂症进行关联研究，筛检精神分裂症易感基因和决定疾病易感性的SNPs。本研究利用人类基因组计划的研究成果，结合中国人群的遗传资源，对精神分裂症研究热点区域进行探索性工作。此项工作将有助于阐明精神分裂症的分子遗传学机制,同时补充完善中国人群SNP和单倍型数据库，具有潜在的经济与社会效益。 方法 本工作在北京大学第六医院住院及门诊收集中国汉族精神分裂症患者临床资料，对患者进行临床访谈和PANSS量表评定，抽取外周血标本，构建中国汉族精神分裂症患者的临床资料数据库及体细胞DNA样本库。通过与北京市血液中心合作，收集正常对照人口学资料及血液样本，构建中国汉族精神分裂症正常对照人群人口学数据库和体细胞DNA样本库。 本研究选取人类染色体8p21区域的3个基因作为候选基因，通过检索NCBI/SNP数据库，对候选基因上一定数目的SNP进行多态性分析，并在SNP之间进行连锁不平衡检验，进而比较这些SNP的等位基因和基因型频率以及所组成的单倍型频率，在精神分裂症患者和正常对照之间进行卡方检验，评价这些频率分布在精神分裂症患者与正常对照之间是否具有统计学差异。通过比较基因频率分布差异的显著性，确定基因与精神分裂症之间是否存在关联。 结果 本项工作对位于人类染色体8p21的三个基因FZD3，FGF17，FGF20上的多个SNP进行了多态性分析，并进行精神分裂症患者和正常对照之间等位基因及基因型频率的卡方检验。 对FZD3基因4个SNP多态性分析显示其中两个SNP的等位基因及基因型频率在精神分裂症患者和正常对照之间具有显著性差异（p < 0.05），由三个SNP组成的单倍型（haplotype）分布在患者组和正常对照之间具有显著的统计学差异（P < 0.000001）。 对FGF17基因上的两个SNP多态性研究显示其等位基因及基因型频率在精神分裂症患者和正常对照之间无显著性差异（p > 0.05）。 对位于FGF20基因3’调节区的一个SNP分析发现其等位基因及基因型频率在精神分裂症患者和正常对照之间具有显著的统计学差异（p < 0.00005）。 结论 1. 此项研究发现FZD3基因SNP等位基因分布及单倍型分布在精神分裂症患者与正常对照之间存在显著性差异，结合本课题组前期工作，共同提示FZD3基因与精神分裂症存在关联，可能与精神分裂症的病因或发病机制有关。 2. 对FGF17基因的研究未发现与精神分裂症之间具有显著的关联，初步认为此基因可能不是精神分裂症的易感基因。 3. 对FGF20基因SNP分析提示精神分裂症和正常对照之间具有显著性差异，结果提示FGF20可能与精神分裂症的发生发展有关，或者该位点与精神分裂症的有效致病基因之间存在紧密连锁。 本研究在国际上首次利用病例对照研究模式研究这三个基因与精神分裂症的关联，其结果应该在更多的研究样本和研究模式中进行重复，并且需要在不同地域，不同种族的研究中加以验证。

【外文文摘】Objective Schizophrenia is a common yet severe psychiatric disorder characterized by profound disturbances of cognition, emotion, and social function. The etiology of schizophrenia is complex, Family and twin studies have shown Genetic factors are the most important in the etiology of the disease, with unknown environmental factors potentially modulating the expression of symptoms The current working hypothesis for schizophrenia is that multiple genes of small to moderate effect confer compounding risk, through interactions with each other and with nongenetic risk factor. A number of loci demonstrate associations with schizophrenia, including chromosome 1, 6, 8, 13, and 22Among them, chromosome 8p21-p22 has been one of the more problematic chromosomes and may harbor candidate genes responsible for the development of schizophrenia. In our study，we selected three genes(FZD3, FGF17 and FGF20) located on the chromosome 8p21-22 region to be candidate genes involved in the association study with schizophrenia. Our study will contribute to the knowledge of the pathogenesis of schizophrenia, which also has a potential value to improve our prevention and treatment of schizophrenia. Method More than 300 unrelated Chinese Han schizophrenia patients and 310 healthy individuals participated in our study. The Schizophrenic patients enrolled in this study were admitted to the sixth hospital, Peking University, Beijing and control subjects included were recruited primarily from social community. Only unaffected subjects who had no known history of psychiatric disease in their families were included in this study. All subjects included in this study were Han nationality, born and living the north area of China. The objectives and procedures of the study were explained to all subjects and written informed consent was obtained. This study was approved by the Ethics committee of Peking University. The genomic DNA was extracted from peripheral leukocytes. PCR and agarose gel electrophoresis were performed to genotype the markers of the FZD3, FGF17 and FGF20 genes. In this study, we investigated a bunch of SNPs on the human the three genes, which have been already registered in the SNP database by the National Center for Biotechnology Information (dbSNP). The allele and genotype frequencies among cases and controls were compared using contingency table and 2-tests. A p-value of less than 0.05 was considered significant. We calculated the pairwise linkage disequilibrium (LD) between the SNPs To estimate Haplotype frequencies and check for statistical significance of differences in haplotype frequencies between patients and control subjects Result 1. The data of FZD3 gene study showed that both genotype and allele frequency distributions between patients and control subjects for the two of the SNPs have a significant differences in frequency of occurrence of the genotype the allele frequencies. The Estimated haplotype frequencies for these three polymorphisms showed a significant difference in patients and control subjects. A strong association was obtained using globe chi-squared test for haplotype analysis (p < 0.001). 2. All the genotypes and alleles we tested in FGF17 showed no significant difference in patients and control subjects. 3.we performed an analysis of the SNP on 3’ untranslated region of FGF20 gene, which showed a great significant difference in patients and control subjects in both the alleles and genotypes frequency of occurrence. Conclusion 1. The results indicated that the FZD3 gene and FGF20 gene might involve in the pathogenesis or be in linkage disequilibrium with a causal locus nearby for schizophrenia. Although there is some positive results have shown in our study, more studies in different methods and in different populations should be done to support our finding. 2. No significant difference in patients and control subjects was found in both the alleles and genotypes frequency of occurrence in the SNP of FGF17, which indicated that the analyzed polymorphism of FGF17gene does not confer a major influence on schizophrenia. Further studies are needed to definitively exclude FGF17 as a potential candidate gene in schizophrenia.