Flow-fluorometric diagnosis of euploid and aneuploid human lymphocytes.

In this paper the potential of flow-fluorometric DNA determination as a convenient and economical alternative to conventional cytogenetics for the diagnosis of aneuploidy in human lymphocytes is explored. By comparing euploid and aneuploid samples, we found that the fluorescence signals emitted from propidium iodide (PI) stained cells are linearly proportional to DNA content. Variation in DNA content between euploid individuals of a given sex was sufficiently low to permit diagnosis of aneuploidy involving chromosomes with greater than 1.8% of the total diploid DNA (e.g., X, 8, 9, and 13). Interindividual DNA content variation with flow fluorometry was too substantial, however, to confidently diagnose trisomy 21. Fluorescent stains which exclude (variant) simple sequence DNA might overcome this limitation.