Quantitative pyrosequencing of heterozygous single nucleotide polymorphisms for rapid diagnosis of Down's syndrome

• Published in: Zhonghua yi xue yi chuan xue za zhi Vol. 26; no. 3; p. 331
• Main Authors: Liu, Xi-qun, Wu, Hai-ping, Bu, Ying, Zou, Bing-jie, Chen, Zhi-yao, Zhou, Guo-hua
• Format: Journal Article
• Language: Chinese
• Published: China 01-06-2009
• Subjects: Alleles; Asian Continental Ancestry Group - genetics; Chromosomes, Human, Pair 21; Cloning, Molecular; DNA - analysis; Down Syndrome - diagnosis; Down Syndrome - genetics; Female; Genetic Testing; Humans; Karyotyping - methods; Polymorphism, Single Nucleotide - genetics; Pregnancy; Prenatal Diagnosis - economics; Prenatal Diagnosis - methods
• ISSN: 1003-9406
• DOI: 10.3760/cma.j.issn.1003-9406.2009.03.021

To establish a method to detect Down's syndrome through quantitative pyrosequencing of the heterozygous single nucleotide polymorphisms (SNPs) on the chromosome 21.
An improved allele-specific-amplification was used to screen heterozygous SNPs on the chromosome 21 from 84 normal samples. Pyrosequencing was used to quantitatively determine the ratio between the two alleles of a heterozygote, and the diagnosis of Down's syndrome was thus carried out based on the ratio.
By genotyping 84 genomic DNA samples from normal Chinese population, 6 SNPs with a relatively high level of heterozygosity were screened out. Heterozygote coverage of 92.9% was achieved by using a panel of 6 SNPs on the chromosome 21. Ten clinical samples from Down's syndrome patients were quantitatively determined by pyrosequencing, and 9 samples were accurately diagnosed by comparing the ratio of the two alleles. The pyrosequencing results showed that the ratio of the two alleles were 2:1 or 1:2 for the Down's syndrome patients.
The method has