唐氏综合征发生原因的循证医学研究

The causes of Down's syndrome:evidence-based research

目的:通过系统性综述(systematic review)的方法,分析我国唐氏综合征发生的原因。方法:通过检索国内外文献数据库,收集符合标准、证据等级较高的文献进行研究。结果:共纳入唐氏综合征病因文献25篇,其中3篇为系统性综述,其余为病例对照研究和横断面研究。现有研究结果未能揭示唐氏综合征明确的发病原因,仅提示发病可能与遗传和环境因素有关。就遗传因素而言,目前关注较多的是MTHFR C667T,MTHFR A1298C,MTRR A66G基因多态性,但缺乏足够证据证实其致病效应。相关文献对环境因素的研究主要集中在孕母年龄,烟酒及接触有毒有害物质等方面,但也未发现较高证据强度的阳性结果。结论:唐氏综合征病因复杂,很多情况下既不是单一因素作用的结果,也不是单因素作用简单叠加的结果,而是多个危险因素相互作用的综合结果。进行唐氏综合征病因学循证研究,开展病因学预防,将为提高人口素质,降低唐氏综合征的发生作出贡献。

Objective： To analyze the causes of Down＇s syndrome by systematic review. Methods： The international and national databases were searched, the literatures with high level of evidence meeting the criteria were collected. Results： 25 literatures about the causes of Down＇s syndrome were included, 3 literatures were systematic reviews, and the other literatures were case - control studies and cross - sectional studies. The current study results failed to reveal the clear etiology of Down＇s syndrome, only suggested the unset of Down＇s syndrome might be related to genetic and environmental factors. In terms of genetic factors, more attention was paid to the polymorphisms of MTHFR C667T gene, MTHFR A1298C gene and MTRRA66G gene, but sufficient evidence was lacked to prove their pathogenic effects. The researches of related literatures on environmental factors focused on maternal age, tobacco ＆ alcohol and exposure to toxic and hazardous substances, but no positive results with evidences of high quality were found. Conclusion ： The etiology of Down＇s syndrome is complex. In many cases, the results come neither because of a single factor, nor the simple sum of single - factors, but interaction of several risk factors. Carrying out evidence - based research for Down＇s syndrome and etiologic prevention will improve the population quality and reduce the incidence of Down＇s syndrome.