Study On Rapid Prenatal Diagnosis Of Down Syndrome

Down syndrome is one of the most common chromosome abnormalities in live-born children, which is caused by the triplicate state of all or a critical portion of chromosome 21. The most impressive phenotype of Down syndrome is mental retardation, which we still have no effective therapy at present. It is very important to pick up the fetus with Down syndrome accurately by means of prenatal diagnosis and terminate the pregnancy before the fetus can be live-born, which is the measure that World Health Organization advocates.Classical prenatal diagnosis technique is cell culture-based so called cytogenetic method. The procedure includes taking amniotic fluid during 16-22 pregnant week and then spending 10-14 days on culturing the cells and the following 1-3 days for making karyotype analysis by G bands technique. This technique is not only time-consuming but also highly risky of culturing failure.As the molecular techniques develop DNA-based prenatal diagnosis techniques are being explored. Real time fluorescence quantitative polymerase chain reaction technique is highly throughput and highly sensitive. We can rely on the technique to amplify quickly, efficiently and quantitatively a critical region on chromosome 21 and measure the gene dosage of Down syndrome.Comparative genomic hybridization (CGH) is a new molecular cytogenetic technique, which is also DNA-based technique so it can overcome the problems related to tissue culturing. CGH can provide genome wide screening for unbalanced chromosomal anomalies efficiently, which has been proved during cancer reaserch. We can try to develop CGH for rapid prenatal diagnosis of Down syndrome.