Rapid Detection of Trisomy 21 Syndrome Use STR-PCR
|Course||Pathology and Pathophysiology|
|Keywords||Short tandem repeats Down syndrome Polymerase chain reaction ( PCR )|
Background Trisomy 21, also known as Down syndrome (Down syndrome, DS), is the most common chromosomal disease. Currently the disease is no effective treatment, trisomy 21 children to the community and the family has brought a heavy burden. The exact etiology and pathogenesis is unclear, it can not do pre-pregnancy intervention, can only be achieved through prenatal diagnosis and therapeutic abortion to prevent the birth of trisomy 21 children. Diagnosis of trisomy 21 children born mainly rely on peripheral blood karyotype analysis technology, but the technology life-cycle is long, cumbersome operation. Trisomy 21 prenatal diagnosis by chorionic villus sampling, amniocentesis, cordocentesis obtain fetal cells for karyotype analysis. But the high cost of these technologies exist, cell culture prone to failure and the strict time requirements and other shortcomings. Fluorescence in situ hybridization (FISH), developed in recent years to have a quick advantage, amniocentesis is a good complement, but expensive general pregnant women is difficult to accept. Although the above method can diagnose chromosome aneuploidy, but then the abnormal chromosome of pro-borne not judge, and can not be detected in a tiny fragment of chromosome 21 duplication caused by Down syndrome. With the development of molecular genetic techniques, a variety of molecular genetic methods for the diagnosis of trisomy 21. In 1995, Fuentes such as trisomy 21 chromosome syndrome critical region (DSCR) located at 21q22.1-q22.2. Selected chromosome 21 on the critical areas of highly polymorphic short tandem repeat sequences (short the tandem repeat, STR) loci using amplified by polymerase chain reaction (poly-merase chainreaction, PCR), non-denaturing polyacrylamide gel electrophoresis, silver nitrate staining techniques, diagnosis of trisomy 21. This method with traditional chromosome analysis compared the advantages for the provincial, simple, low cost, and STR-PCR technique can detect the critical regions tiny fragment repeated due to Trisomy 21, assisted chromosome analysis can be improved with Down syndrome detection rate. Objective To investigate the value of STR-PCR technology in the diagnosis of Down syndrome, the establishment of a fast and efficient diagnosis of Down syndrome molecular genetic methods, analysis of the auxiliary peripheral blood and amniotic fluid cell karyotype. Materials and methods. Subjects including 60 cases karyotype analysis of peripheral blood for trisomy 21 children and their parents in peripheral blood and 50 amniotic fluid samples and some fetal parents peripheral blood. 2 Research Methods chromosome 21 critical region and near eight STR loci, primer sequences from GenBank. Specimen DNA, extracted using Chelex method using polymerase chain reaction amplification, non-denaturing polyacrylamide gel electrophoresis, silver nitrate staining techniques, by observing the electrophoretic bands diagnosis of trisomy 21. The experimental results of 1.60 cases of 21 children with trisomy 58 cases were detected, the detection rate was 96.7%. . Peripheral blood samples from 49 patients extra chromosome 21 from the mother, and five cases from his father, four cases can not judge pro-borne. 3.50 amniotic fluid specimens detected 10 cases of trisomy 21 children, nine cases of amniotic fluid cell chromosome analysis, analysis of amniotic fluid cell karyotype 46, XY. Eight cases of the extra chromosome 21, and 1 case of part of chromosome 21 fragments from the mother, and patients with extra chromosomes from the father. 4 the integrated peripheral blood and amniotic fluid results eight STR loci D21S1409, D21S1433, D21S11, D21S1444, D21S1437, D21S1414, D21S1442, D21S1809 heterozygosity is: 0.69,0.84,0.88,0.81,0.75,0.79,0.82,0.68, trisomy 21 detection rate: 30%, 61%, 67%, 59%, 43%, 45%, 58%, 27%. 97% of the joint use of the eight sites on the detection rate of trisomy 21. Conclusion 1. Institute selected eight STR loci are highly polymorphic, with high heterozygosity, better genetic markers. 2 In this study, the combination of eight STR loci, trisomy 21 syndrome detection rate reached 97%, indicating that the STR-PCR technology is a fast, simple method of detecting trisomy 21 syndrome, can be assisted chromosome The type of analysis, diagnosis of Trisomy 21. 3.STR-PCR technology can determine the origin of extra chromosome, the development of molecular genetics methods to further explore the Trisomy 21 hair not the to to fight snail Lu ? Trisomy 21 diagnosis has opened up a new road.