High-resolution chromosome analysis in clinical medicine.

The field of human cytogenetics has expanded considerably in the past few years due, to a large extent, to the application of the metaphase banding techniques. Among many advances, the chromosomal abnormalities involved in over thirty newly discovered syndromes have been defined and consistent chromosome defects have been observed in several neoplasias. Very recent improvements in culture techniques through cell synchronization and in chromosome treatments, such as the use of minimal exposure to colcemid and/or the use of agents that inhibit chromosome condensation, allow for the routine utilization of highly elongated and finely banded prophase chromosomes. These new techniques are being used clinically to uncover previously undetectable chromosome defects, to localize the exact break points involved in numerous duplication-deficiencies known in man, and to establish possible phenotype-genotype relationships at a refined level.