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April 1975

New Chromosomal Syndromes

Author Affiliations

From the Medical Genetics Division, Department of Laboratory Medicine and Pathology, University of Minnesota, Medical School, Minneapolis.

Am J Dis Child. 1975;129(4):515-529. doi:10.1001/archpedi.1975.02120410075021

The field of human cytogenetics has changed considerably since 1891 when Hansemann studied chromosomes in human cells and attempted to assign a chromosome number to them.1 The first important discovery was made in 1949 by Barr and Bertram when they observed the sex chromatin body, a small, darkly staining chromatin mass present in the interphase nuclei of females2 (Fig 1, left). This discovery later made possible the presumptive diagnosis of Turner and Klinefelter syndromes by the simple analysis of a buccal smear. After 1956, when Tjio and Levan together developed a simple technique that made possible the study of human chromosomes,3 the field progressed rapidly. During the ensuing five years, the causes of trisomy 13, 18, and 21 syndromes; Turner syndrome, and Klinefelter syndrome were established. The next five years saw the application of autoradiography for better identification of chromosomes and the delineation of more subtle chromosome

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