智力低下的病因学是一个相当复杂的问题,包括多方面的因素,病因分类也有不同的意见。当前较通用的是按照医学观点,以现有诊断技术为手段,将智力低下分为两大类即伴有与不有伴医学异常发现的智力低下。这两大类中各自的主要病因分析见表1。 国内外有关智力低下病因分析的报告中均发现重度智力低下患儿几乎全部伴有医学异常发现。全部智力低下中具有生物医学异常者所占比例报告不一,国外为20～25％,我们的材料为50～60％。 智力低下是由于多因素作用的结果,包括由小儿本身神经解剖、病理、生理生化等 Etiology of mental retardation is a rather complex issue, including many factors, the etiology of classification also have different opinions. The current more common is in accordance with the medical point of view, the existing diagnostic techniques as a means to lower mental retardation is divided into two categories, namely with and without medical abnormalities found in mental retardation. The main causes of these two categories in Table 1. Domestic and international reports on the cause of mental retardation were found in children with severe mental retardation, almost all accompanied by medical findings. All mental retardation biomedical abnormalities accounted for the proportion of different reports, foreign 20 to 25%, our material is 50 to 60%. Mental retardation is the result of multi-factorial effects, including neurological anatomy, pathology, physiology and biochemistry