徐周洋,劉欣
COMT Val158Met 基因多態(tài)性與精神分裂癥發(fā)病風(fēng)險(xiǎn)的Meta分析
徐周洋,劉欣
目的:探討COMT基因多態(tài)性與精神分裂癥患病風(fēng)險(xiǎn)的相關(guān)性。方法:在PubMed、CNKI、CBM、EMBASE、MEDLINE和萬(wàn)方數(shù)據(jù)庫(kù)中用計(jì)算機(jī)檢索相關(guān)文獻(xiàn),運(yùn)用Meta分析方法對(duì)納入文獻(xiàn)進(jìn)行綜合定量及亞組分析。計(jì)算合并相對(duì)比值比(OR)和95%可信區(qū)間(95%CI),使用Review Manager 5.1軟件進(jìn)行分析。結(jié)果:入選文獻(xiàn)17篇,包括病例組4 935例和對(duì)照組4 282例。COMT基因多態(tài)性與精神分裂癥并無(wú)相關(guān)性(雜合子比較,=0.07,I2=1%;隱形遺傳模式比較,=0.11,I2=0%)。亞組分析中,無(wú)論是高加索人群還是亞洲人群,COMT基因多態(tài)性與精神分裂癥發(fā)病風(fēng)險(xiǎn)無(wú)統(tǒng)計(jì)學(xué)依據(jù)(>0.05)。結(jié)論:COMT基因多態(tài)性與精神分裂癥患病風(fēng)險(xiǎn)可能無(wú)相關(guān)性。
COMT;基因多態(tài)性;精神分裂癥;Meta分析
精神分裂癥(Schizophrenia)是以精神障礙為特征的一類最常見精神病[1],以基本個(gè)性改變,思維、情感、行為的分裂,精神活動(dòng)與環(huán)境不協(xié)調(diào)為主要特征[2],是一種嚴(yán)重影響人類健康的多發(fā)性疾病,具有顯著的家族聚集性[3]。研究表明,本病一級(jí)親屬的終身患病率達(dá)10%,為一般群體患病率的10倍[4]。精神分裂癥的癥狀表現(xiàn)多樣,典型癥狀涵蓋多個(gè)精神領(lǐng)域的功能障礙,包括感知、內(nèi)在思維、語(yǔ)言、注意力、社交能力、情感表達(dá)、意志力等[5]?;蜃兓?、環(huán)境因素及基因與環(huán)境的相互作用被認(rèn)為是該病的主要原因。
COMT(catechol-O-methyltransferase)是在人大腦中分解多巴胺和去甲腎上腺素類的一種代謝酶[6],通過(guò)促進(jìn)S-腺苷甲硫氨酸的甲基化,從而使兒茶酚胺類(包括多巴胺)神經(jīng)遞質(zhì)失活,故被認(rèn)為是與精神分裂癥關(guān)系最為密切的酶[7]。COMT基因是精神分裂癥最重要的候選基因之一,該基因位于人類染色體22q11區(qū)域,多項(xiàng)研究表明,染色體22q11區(qū)域與精神分裂癥密切相關(guān)[8]。COMT基因多態(tài)性(如)可影響酶的活性,為高活性酶等位基因,為低活性酶等位基因,該多態(tài)性控制的酶活性可改變3~4倍[9]。對(duì)COMT基因多態(tài)性的多項(xiàng)研究顯示,與精神分裂癥發(fā)病,以及認(rèn)知行為、暴力傾向、自殺傾向密切相關(guān)[10-18]。其他類似研究則表明COMT基因多態(tài)性與精神分裂癥發(fā)病風(fēng)險(xiǎn)并無(wú)相關(guān)性[19-27]。
1.1 文獻(xiàn)的收集
1.1.1 文獻(xiàn)檢索 使用 MEDLINE、PubMed、EMBASE文獻(xiàn)數(shù)據(jù)庫(kù)檢索英文全文文獻(xiàn),英文檢索詞為“COMT、gene polymorphism、schizophrenia”。使用中國(guó)生物醫(yī)學(xué) 數(shù)據(jù)庫(kù)(Chinese Bio-medicine Database,CBM)、中國(guó)知網(wǎng)(CNKI)、萬(wàn)方數(shù)據(jù)知識(shí)服務(wù)平臺(tái)等中文文獻(xiàn)系列數(shù)據(jù)庫(kù),中文檢索詞為“COMT、基因多態(tài)性、精神分裂癥”,檢索中文期刊全文文獻(xiàn),檢索時(shí)間為1996~2012年。同時(shí)也采用文獻(xiàn)追溯的方法。
1.1.2 納入文獻(xiàn)標(biāo)準(zhǔn) ①采用病例對(duì)照設(shè)計(jì),且研究對(duì)象為精神分裂癥患者,對(duì)照組為健康人群;②有各種基因型頻率的數(shù)據(jù);③對(duì)照研究資料的基因型頻率分布滿足哈迪 -溫伯格平衡定律(Hardy-Weinberg equilibrium,HWE);④所有精神分裂癥患者的臨床診斷依據(jù)符合美國(guó)精神障礙診斷與統(tǒng)計(jì)手冊(cè)第(3/4)版(DSM-Ⅲ/Ⅳ),并由兩名主治醫(yī)師分別獨(dú)立診斷;⑤對(duì)照組為無(wú)精神分裂癥家族史的健康人群;⑥文獻(xiàn)中基因型數(shù)據(jù)與先前發(fā)表的文獻(xiàn)無(wú)重復(fù)。
1.2 數(shù)據(jù)提取
由2名獨(dú)立的研究者對(duì)入選文獻(xiàn)的數(shù)據(jù)進(jìn)行錄入并核對(duì),摘錄的主要內(nèi)容包括研究者姓名、發(fā)表雜志和年份、病例和對(duì)照者的數(shù)量、等位基因及基因型的分布頻率等。如同一個(gè)研究報(bào)告中涉及相同的人群,則每一個(gè)人群均以單獨(dú)的研究入選。如一組人群的研究以不同的形式或語(yǔ)言發(fā)表在不同雜志,則選擇其中數(shù)據(jù)資料最完整的研究納入。為確保盡可能多的研究入選以增加Meta分析的可信性,部分資料缺失的研究,通過(guò)與研究者之間進(jìn)行聯(lián)系以補(bǔ)充完善。
1.3 統(tǒng)計(jì)學(xué)處理
以比數(shù)比(odds ratio,OR)及其95%可信區(qū)間(95%confidence intervals,CIs)評(píng)價(jià)基因多態(tài)性與精神分裂癥之間的關(guān)聯(lián)強(qiáng)度。在每個(gè)研究中,分別對(duì)病例組和對(duì)照組內(nèi)等位基因的頻率、基因型分布情況進(jìn)行分析,在評(píng)估致病基因的效能時(shí),不僅對(duì)其純合子的致病風(fēng)險(xiǎn)進(jìn)行評(píng)估,同時(shí)也對(duì)其攜帶者(雜合子和純合子)相對(duì)于野生型純合子的致病風(fēng)險(xiǎn)進(jìn)行評(píng)估。并按照種群分為亞洲人群亞組和高加索人群亞組。應(yīng)用Meta分析軟件Review Manager 5.1.軟件進(jìn)行數(shù)據(jù)整理和分析,對(duì)各文獻(xiàn)結(jié)果進(jìn)行一致性檢驗(yàn),并根據(jù)檢驗(yàn)結(jié)果選用相應(yīng)的數(shù)據(jù)合并方法,若各研究間無(wú)顯著異質(zhì)性,則采用固定效應(yīng)模型進(jìn)行數(shù)據(jù)合并,否則,則采用隨機(jī)效應(yīng)模行數(shù)據(jù)合并,計(jì)算總OR值。
2.1 納入文獻(xiàn)特征
共搜索到英文文獻(xiàn)313篇和中文文獻(xiàn)41篇。通過(guò)文章題目、摘要以及文獻(xiàn)內(nèi)容的閱讀,依據(jù)納入文獻(xiàn)標(biāo)準(zhǔn),排除299篇英文和37篇中文文獻(xiàn),1篇文章使用的數(shù)據(jù)重復(fù)因此排除,見圖1。最后17篇文獻(xiàn)符合本研究納入標(biāo)準(zhǔn),其中英文文獻(xiàn)14篇、中文文獻(xiàn)3篇;病例組4 935例,對(duì)照組4 282例;高加索人群研究9篇,亞洲人群研究8篇,見表1。對(duì)照組均符合HWE平衡定律,均用聚合酶鏈反應(yīng)(PCR)方式檢測(cè)COMT基因,診斷標(biāo)準(zhǔn)均符合DSM-Ⅲ/Ⅳ,并由兩名主治醫(yī)師分別獨(dú)立診斷。
圖1 搜索流程圖
2.2 Meta分析
敏感度分析及偏倚分析,在各基因模型與精神分裂癥關(guān)系的分析中,去除權(quán)重最大的研究或變換分析模型均未對(duì)結(jié)果造成影響,提示結(jié)果穩(wěn)定。漏斗圖顯示無(wú)明顯不對(duì)稱,除了一點(diǎn)偏差較遠(yuǎn)外,其余各點(diǎn)基本呈漏斗狀分布,見圖3。本研究17篇文獻(xiàn)的 Eggers偏系數(shù)為 1.36(= 0.137)說(shuō)明合并分析的結(jié)果穩(wěn)定性好,基本可靠。
表1 Meta分析中納入研究的特征
表2 COMT Val158Met 基因多態(tài)性與精神分裂癥發(fā)病風(fēng)險(xiǎn)Meta分析結(jié)果
精神分裂癥的概念自Kraepliin提出早發(fā)癡呆至今已有百年[28]。在21世紀(jì)中國(guó)疾病負(fù)擔(dān)問(wèn)題研討會(huì)上,精神疾病已列為疾病負(fù)擔(dān)的第一位。但是,精神分裂癥的病因并不十分明確。多項(xiàng)研究已證實(shí)遺傳在精神分裂癥的發(fā)病因素中占重要地位。近年來(lái)有關(guān)精神分裂癥的基因研究報(bào)道很多,但尚無(wú)突破性進(jìn)展。大量的研究已表明COMT基因多態(tài)性與精神分裂癥的發(fā)病風(fēng)險(xiǎn)有明確的相關(guān)性[10-18],而且相關(guān)基因機(jī)制研究也有大量的報(bào)道,而其他相關(guān)研究則否定其相關(guān)聯(lián)系,COMT基因多態(tài)性與精神分裂癥發(fā)病風(fēng)險(xiǎn)的關(guān)系仍存在很大爭(zhēng)議。
Meta分析是指用統(tǒng)計(jì)學(xué)方法對(duì)收集的多個(gè)研究資料進(jìn)行分析和概括,以提供量化的平均效果來(lái)回答研究的問(wèn)題,其優(yōu)點(diǎn)是通過(guò)增大樣本含量來(lái)增加結(jié)論的可信度,解決研究結(jié)果的不一致性。Meta分析是對(duì)同一課題的多項(xiàng)獨(dú)立研究的結(jié)果進(jìn)行系統(tǒng)的、定量的綜合性分析。它是文獻(xiàn)的量化綜述,是以同一課題的多項(xiàng)獨(dú)立研究的結(jié)果為研究對(duì)象,在嚴(yán)格設(shè)計(jì)的基礎(chǔ)上,運(yùn)用適當(dāng)?shù)慕y(tǒng)計(jì)學(xué)方法對(duì)多個(gè)研究結(jié)果進(jìn)行系統(tǒng)、客觀、定量的綜合分析。但是統(tǒng)計(jì)學(xué)上的合并也不可避免地帶來(lái)許多混雜因素,如發(fā)表的偏倚性、各實(shí)驗(yàn)室基因檢測(cè)水平的不一致性、各人群基因遺傳的差異性等。這些因素的存在會(huì)在一定程度上影響到Meta分析的合并效應(yīng)量的可靠性。因此開展更多設(shè)計(jì)合理的隨機(jī)對(duì)照研究,將研究結(jié)果納入Meta分析以解決這一問(wèn)題,從而對(duì)COMT基因多態(tài)性與精神分裂癥的關(guān)系作一個(gè)更加合理、可靠的結(jié)論。
圖2 COMT基因多態(tài)性與精神分裂癥發(fā)病風(fēng)險(xiǎn)的森林圖(MM v.s.VM+VV)
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圖3 COMT基因多態(tài)性與精神分裂癥總體人群上發(fā)病風(fēng)險(xiǎn)的漏斗圖(MM v.s.VM+VV)
(本文編輯:王晶)
COMT Val158Met Gene Polymorphisms and Schizophrenia Susceptibility:A Meta Analysis
Background:To evaluate the correlation of COMTgene with susceptibility to schizophrenia.Methods:A meta-analysis was performed by searching the published literatures in PubMed,CNKI,CBM, EMBASE,MEDLINE and Wanfang databases.Overall and subgroup analyses were performed.Odds ratio(OR) and 95%confidence interval (CI)were used to evaluate the associations between COMTpolymorphisms and schizophrenia risk.Statistical analysis was performed with Review Manager 5.1.Results: Seventeen studies addressing COMTpolymorphisms were analyzed among a total of 4 935 schizophrenic cases and 4 282 controls.There was no evidence that the COMTpolymorphism was associated with an increased schizophrenia risk (>0.05)in over all populations(heterozygote comparison,= 0.07,I2=1%;recessive model comparison,=0.11,I2=0%).In subgroup analysis based on ethnic groups,no associations was found in Caucasus and Asians(>0.05).Conclusion:It is likely that the COMTgene polymorphism does not confer susceptibility to schizophrenia.
COMT;gene polymorphism;Schizophrenia;Meta-analysis
R741;R749.3
A DOI 10.3870/sjsscj.2014.04.012
武漢市優(yōu)撫醫(yī)院精神科二病區(qū)武漢430000
2013-10-11
徐周洋315313799@qq.com