Novel real-time PCR assay for rapid prenatal diagnosis of Down syndrome: a prospective study of 563 amniocytes.

Objective: To explore the possibilities of a novel real-time PCR assay for rapid prenatal diagnosis of Down syndrome in clinical settings.

Design And Methods: This duplex real-time PCR assay is based on relative quantification of DSCR4 gene on chromosome 21 by using RABIF gene on chromosome 1 as a reference. For each sample, the differences in threshold cycles between DSCR4 and RABIF genes (Delta Ct, DeltaCt) were detected, and a calibrated DeltaCt value (DeltaDeltaCt, DeltaCt (sample)-DeltaCt (internal control)) was analyzed.

[Establishment of lymphocyte cell lines with abnormal chromosome karyotypes and its application in external quality assesment for chromosome karyotype analysis].

Objective: To develop chromosome abnormal karyotype quality control cell and to explore the external quality assessment (EQA) method for chromosome karyotype analysis.

Methods: The chromosome abnormal karyotype quality control cells were prepared by EB virus (EBV) transfection of human B lymphocyte strain establishment and were distributed to participating labs for EQA test of chromosome karyotype analysis project at appointed time. The evaluation results were obtained through 4 grades scoring.