Porter I H
J Reprod Med. 1976 Jul;17(1):3-18.
In 1956 the correct number of chromosomes was established in man, and in 1959 the well-recognized syndromes of Down, Turner and Klinefelter were shown to be associated with chromosomal anomalies. During the following 10 years more than 100 chromosomal anomalies were discovered by what now appear to have been rather crude and undiscriminating techniques, as reflected in the repeated attempts to standardize the human karyotype, first at Denver in 1960, then in London in 1963 and in Chicago in 1966. At the Second Denver Conference in 1970 a dramatic change took place as a result of the introduction of a technique by which every individual chromosome could be distinguished; by the time the next Conference on Standardization in Human Cytogenetics was held, in Paris in 1971, additional techniques had been developed that could distinguish not only every chromosome but also different regions of each chromosome. We are now able to define normal variants reliably, identify extra chromosomes involved in abnormalities accurately, recognize small defects which were missed previously and map structural defects precisely by tracing exchange segments of chromosomes. Cytogenetics should be used by the clinician to establish a diagnosis as a guide to a rational plan of management, as a guide to prognosis and genetic counseling and for monitoring pregnancies in people at increased risk of having children with defects associated with chromosomal anomalies.
1956年确定了人类染色体的正确数目，1959年发现唐氏、特纳和克兰费尔特等广为人知的综合征与染色体异常有关。在接下来的10年里，通过当时看来相当粗糙且缺乏区分性的技术发现了100多种染色体异常，这反映在多次尝试对人类核型进行标准化上，先是1960年在丹佛，然后是1963年在伦敦，1966年在芝加哥。1970年在第二届丹佛会议上，由于引入了一种能区分每一条个体染色体的技术，发生了巨大变化；到1971年在巴黎举行下一次人类细胞遗传学标准化会议时，又开发出了其他技术，这些技术不仅能区分每一条染色体，还能区分每条染色体的不同区域。我们现在能够可靠地定义正常变异，准确识别与异常相关的额外染色体，识别以前遗漏的小缺陷，并通过追踪染色体的交换片段精确绘制结构缺陷图谱。临床医生应使用细胞遗传学来确立诊断，以此作为合理管理计划的指南、预后和遗传咨询的指南，并用于监测生育有与染色体异常相关缺陷孩子风险增加人群的妊娠情况。
