Comparison of classical cytogenetics versus interphase FISH in diag- nosis of mosaic form of Turner syndrome

Background: Mosaic form of turner syndrome that represented by two or more cell lines in an affected individual, often has limitation for detection with classical cytogenetic methods. The present study was carried out to compare the efficiency of interphase Fluorescence In Situ Hybridisation (FISH) and cytogenetic techniques in detection of mosaic form of turner syndrome Methods: All candidate samples for turner syndrome were surveyed with both interphase FISH using DXZ1 as a chromosome X specific probe and the GTGbanding methods. The chi square test was used and a P-value of less than 0.05 was considered as being significant. Results: Asignificant difference was observed between results obtained from the application of the two methods under study (P<0.05), indicating that the interphase FISH is favourably compares to conventional cytogenetics in detection of mosaic form of X chromosome aneuploidy, as an extended number of cells can be scored in a limited time. Conclusion: The results indicate that using the two techniques in parallel allow accurate differentiation between mosaicism and homogenous aneuploidy of X chromosome, and thus both numerical and structural aberrations of the X will be analyzed.