Detection of Chromosomal Aneuploidy in uncultured Amniotic Fluid by FISH (Fluorescence in situ Hybridization)

Abstract

Objective to test the specificity and sensitivity of FISH in detection of chromosomal aneuploidies in uncultured amniotic fluid. Design Descriptive study. Department of Pathology, Faculty of Medicine, Srinakharinwirot University.

Subjects Twenty amniotic specimens, 5 with normal karyotype, 12 with chromsome numerical aberration in the first culture and 3 amniotic specimens which suspected to have chromosomal aneuploidy.

Results The number of hybridization signals (0,1,2,3) represented the chromosome copy number. Therefore the specific chromosome copy number was evaluated by counting the number of the hybridization signals. The FISH signals in monosomic (1 signal), disomic (2 signals) and trisomic (3 signals) nuclei could be identified clearly. The distributions of monosomic, disomic and trisomic cells differ significantly. It is possible to discriminate between monosomy, disomy and trisomy. The result of the chromosmal aneuploidies in all of the 15 tested specimens by interphase FISH were concordance to the cytogenetic results.

Conclusion The interphase FISH tecnique provides rapidly and efficiency result for the detection and confirmation of chromosomal aneuploidies. From these preliminary studies indicate that the technique can be very efficient for detection of specific aneuploidy in 1) confirmation of the cytogenetic result, 2) suspected case of chromosomal abnormality and 3) known case of familial balanced translocation.