Determination of sensitivity and specificity of a novel gene dosage assay for prenatal screening of trisomy 21 syndrome.

Ahmad Reza Kamyab (1) , Fahimeh Shahrokhi (1) , Elmira Shamsian (1) , Mina Hayat Nosaied (1) , Parvin Dibajnia (2) , Mehrdad Hashemi (3) , Reza Mahdian (1)

1 Molecular Medicine Department
2 Psychiatrics Department
3 Science and Research branch

OBJECTIVE: To compare the gene dosage results achieved by a novel multiplex quantitative assay with cytogenetic and quantitative fluorescent polymerase chain reaction (QF-PCR) analysis for prenatal screening of trisomy 21 syndrome on corresponding fetal samples. DESIGN AND METHODS: Fetal samples (n=134) were collected from pregnant women considered high risk for having trisomy 21 affected fetus. Cytogenetic analysis and QF-PCR were performed. Then, the relative gene dosage of DSCAM and DYRK1A2 genes was determined on corresponding samples using comparative delta cycle of threshold (ΔC(T)) method. RESULTS: The mean gene dosage ratio was 1.55 ± 0.11 (95% CI:1.51-1.58) in trisomy 21 cases and 1.01 ± 0.12 (95% CI:0.98-1.03) in normal samples (p value<0.001). The results were in agreement to the results of cytogenetic and QF-PCR analysis with the overall specificity of 0.96 (95% CI:0.91-0.98) and the sensitivity of 0.80 (95% CI:0.49-0.94). CONCLUSIONS: This gene dosage assay is appropriate for the screening of high risk pregnant women and is readily amenable to automation.

Keywords: Down syndrome; Prenatal screening; Gene dosage; Real-Time polymerase chain reaction

Domains: Cancer

Ahmad Reza Kamyab, Fahimeh Shahrokhi, Elmira Shamsian, Mina Hayat Nosaied, Parvin Dibajnia, et al.. Determination of sensitivity and specificity of a novel gene dosage assay for prenatal screening of trisomy 21 syndrome.. Clinical Biochemistry, 2012, 45 (3), pp.267-71. ⟨10.1016/j.clinbiochem.2011.11.013⟩. ⟨pasteur-00759565⟩