Potential Use Of Blood, Buccal And Urine Cells For Rapid Noninvasive Diagnosis Of Suspected Aneuploidy Using Fluorescence In Situ Hybridization (FISH)

Objective: The objective of the study was to determine whether noninvasive and readily available cells could be used for rapid diagnosis of specific chromosomal abnormality to facilitate management of patients in acute/specialized situation. Methods: In the present study we analyzed blood, buccal & urine cells from 3 patients with pure trisomy 21 with locus specific FISH probes for chromosome 21. Three normal subjects were included for comparison. The clinical cases were confirmed with conventional cytogenetic studies of peripheral lymphocytes before inclusion in the study. Result: Average frequencies for 1, 2 and 3 hybridization signals were 2.2%, 6% and 91% for blood cells, 2.5%, 7% and 89.8% for buccal cells and 2%, 9.3% and 87.4% for urine cells, respectively in the cases. False trisomic cells were less than 1% in all type of cells in controls. False monosomic cells were 3.6%, 4.5% & 9.8% for blood, buccal & urine cells in controls which was quite similar to alphoid FISH probes (chromosome 1 & 18). Conclusion: This study suggests DNA locus specific FISH probes can be used in blood/buccal/urine cells for rapid noninvasive diagnosis, but because of high rates of false monosomy, it may not be accurate to diagnose low (<10%) level of mosaicism. The test is suitable for medically urgent situations for management guidance.