Objective: To study the technique and diagnostic value of fluorescence in situ hybridization (FISH) in chromosome abnormality for prenatal diagnosis.
Methods: Amniocenteses were performed in 34 pregnant women of 16-23 gestational weeks with indications for prenatal diagnosis. The amniotic fluid samples were cultured in Chang's medium. The metaphase chromosomes were hybridized in situ with the human centromere probes, alpha-satellites DNA probes of X, Y, 13, 21, 18 chromosomes and all primer chromosome probes. These probes were conjugated by Biotin and Dioxin then. The treated slides were examined and taken photos under the fluoromicroscope.
Results: By FISH technique, normal karyotypes were shown in 31 cases: 16 cases of 46, XY, 15 cases of 46, XX. Abnormalities were found in 3 patients which were 47, XY + 21; 47, XY + 18 and 45, X/46, X, r (X) respectively.
Conclusion: Using FISH technique to detect chromosome abnormalities in amniotic fluid for prenatal diagnosis is a reliable method which is rapid and accurate. It has higher sensitivity and specificity in finding chromosome structure abnormalities and marking chromosome DNA sequences.