本文综述了发育异常领域的一些重要问题，可能有利于理解基本发育过程，以及毒物对该过程干扰的机理。大约７０％的人体发育异常是病因不明的，人们历来以为这些缺陷是由于在器官形成期接触化学或物理因素所致。现在已有令人信服的证据表明，在器官形成前的发育阶段接触某些因子也可直接损害所接触的早期孕体，从而导致胚胎异常。于是，着床前或着床后接触毒物可引起正常发育过程中协调连锁事件的基因控制的“越轨”（ｄｅｒａｉｌｍｅｍ）。如发育异常可因发育基因的协调表达紊乱所致，其中包括染色体印迹（ｇｅｎｏｍｉｃｉｍ－ｐｒｉｎｔｉｎｇ）、细胞系特化、细胞混合和识别、细胞间相互作用、细胞迁移、分化及分裂等，取决于接触的时间。由于我们缺乏化学物引起发育异常的分子和细胞学基础，目前只能利用一系列假设来评价和解释发育毒理学研究所得的资料。因此，研究正常和异常发育机理以及人和实验动物之间药代动力学—药效学的关系，是建立合适的危险度评价假设和剂量反应以描述人群发育毒性危险度的关键 This article reviews some important issues in the field of developmental abnormalities and may be useful in understanding the underlying developmental processes and the mechanisms by which toxins interfere with the process. Approximately 70% of human dysplasias are etiologic and it has always been assumed that these defects result from exposure to chemical or physical factors during organogenesis. There is now convincing evidence that exposure to certain factors during the pre-organogenesis stage can also directly affect the exposed early gestational age, leading to abnormal embryos. Thus, contact with a poison before or after implantation can cause a “derailmem” of gene control that coordinates the chain of events during normal development. Developmental abnormalities can be caused by disturbances in the coordinated expression of developmental genes, including genomicim-printing, cell line characterization, cell mixing and recognition, cell-cell interactions, cell migration, differentiation and division, time. Due to our lack of molecular and cytological basis for developmental abnormalities caused by chemicals, currently only a number of hypotheses can be used to evaluate and interpret data from developmental toxicology studies. Therefore, studying the mechanisms of normal and abnormal development and pharmacokinetics-pharmacodynamics between humans and experimental animals is the key to establishing appropriate risk assessment assumptions and dose response to characterize the risk of developmental toxicity in the population