Fatemeh Namazi Shabestari - Department of Genetics, Islamic Azad University, Ahar. I.R. Iran
Mehdi Ghiami Rad - Department of Genetics, Islamic Azad University, Ahar. I.R. Iran.
Keivan Majidzadeh Ardabili - Department of Medical Genetics, AJA university of Medical Sciences, Tehran, I.R. Iran.
Habib Nasiri - Department of Medical Genetics, AJA university of Medical Sciences, Tehran, I.R. Iran.

Introduction: The current method to detect chromosomal abnormalities (i.e., cell culture and karyotyping) is timeconsuming.Thus, genetics scientists have been challenged to make quick and accurate diagnosis techniques such as molecular cytogenetic techniques including MLPA, FISH and QF-PCR. However, these techniques require expensive and sophisticated equipment offered only in modern laboratories. Consequently, their accessibility to the public is highlylimited. On the other hand, quick diagnosis and timely abortion (before the 16th week of pregnancy) are particularlysensitive in Muslim states including Iran, due to religious reasons. Objective: This study aimed to evaluate the accuracy of the microtitre plate reverse hybridization assay relative to the QFPCRfor prenatal diagnosis of Down syndrome. Methods: APP and GAPDH genes were amplified as the copy number markers of chromosomes 21 and 12 (as control),respectively. The amount of labeled PCR products was assessed after hybridization with specific probes and a colorimetricassay. Then the results obtained for the relation of APP OD/GAPDH OD were calculated in the cases of Down syndromeand normal samples. The designed method used and the QF-PCR technique were simultaneously in a double blind mannerto detect Down syndrome in 100 prenatal samples. Results: The finding of microtiter plate reverse hybridization assay was also confirmed by comparing of the present resultswith those of the QF-PCR. The sensitivity and specificity of microtitre plate reverse hybridization assay was determined100%. Therefore, due to full compliance of the results of microtitre plate reverse hybridization assay and QF-PCR in the examined samples, it can be concluded microtiter plate reverse hybridization assay has enough potential to be used for rapid detection of aneuploidies in prenatal samples.

Down syndrome, Microtitre plate reverse hybridization assay,Molecular cytogenetic, Prenatal diagnosis, QF-PCR