DNA cytophotometry in pre-natal cytogenetic diagnosis

DNA cytophotometry was used to resolve a cytogenetic ambiguity involving a possible deletion of part of the short arm of chromosome 18 in cells obtained by amniocentesis. Measurements of chromosomal DNA content were within normal limits. This is the first time that DNA cytophotometry has been used in cytogenetic diagnosis; it illustrates the potential of this new approach to cytogenetics.