Study of pregnant women with high risk of fetus abnormalities by routine cytogenetics method (karyotyping) and molecular method (FISH) by using X and Y probs and comparing the advantages and disadvantages of these methods in the northwest of Iran's patients

Background: The health of the fetus during the 9 months of pregnancy is very important for every pregnant couple. Identifying carriers of the genetic diseases and their diagnosis before birth, controls the disease's prevalence and does not impose huge costs on the patient's family and community. This study aimed to evaluate the rapid prenatal diagnosis importance in the chromosomal abnormalities identification.

Methods: 50 amniotic fluid samples were studied by karyotyping and fluorescence in situ hybridization (FISH). Karyotyping was performed on me taphase chromosomes to identify all the chromosomal abnormalities and FISH detected chromosomal abnormalities by using X and Y probs, as the rapid method.

Results: We identified one cases of Down syndrome (2%), three cases of extension in the polymorphism region of P arms of chromosome 15(15p+) (6%), one cases of extension in the polymorphism region of chromosome 9 (9 qh+) (2%), one case of peristaltic inversion in chromosome Y (2%), one case of XYY mosaic embryo, 46, XY /47, XYY variant (2%) and one case with the extra unknown segment on P arms of chromosome 15 (2%).

Conclusion: FISH is a useful method with high sensitivity to provide rapid results for couples who don't have enough time to end their pregnancy legally. In cases of X-linked diseases, it is a reliable method to learn the sex of the fetus. FISH is not able to detect structural anomalies, therefore karyotyping is required for absolute right outcomes of chromosome abnormalities.