title: Allelic methylation status of CpG islands on chromosome 21q in patients with Trisomy 21.
abstract: Trisomy 21 is a chromosomal condition caused by the presence of all or part of an extra 21st chromosome. There has been limited research into the DNA methylation status of CpG islands (CGIs) in trisomy 21, therefore, exploring the DNA methylation status of CGIs in 21q is essential for the development of a series of potential epigenetic biomarkers for prenatal screening of trisomy 21. First, DNA sequences of CGIs in 21q from the USCS database were obtained and 149 sequences and 148 pairs of primers in the BGI YH database were aligned. All 300 cases were analyzed by a heavy methyl-polymerase chain reaction (HM-PCR) assay and a comparison of the DNA methylation status of CGIs was made between trisomy 21 and the control. The HM-PCR assay results did not show a difference in the DNA methylation status between individuals with trisomy 21 and the control. In total, there were 11 CGIs that showed various DNA methylation statuses between Japanese and Chinese patients. Subsequently, bisulfite genomic sequencing found variations in the methylation status of CpG dinucleotides in CGIs (nos. 14, 75, 109, 134 and 146) between trisomy 21 and the control. The different DNA methylation status of CpG dinucleotides in CGIs may be a potential epigenetic marker for diagnosing trisomy 21. No difference was identified in the DNA methylation status of 21q CGIs among Chinese individuals with trisomy 21 and the control. The homogeneity of the DNA methylation status of 21q CGIs in Chinese patients indicates that DNA methylation is likely to be an epigenetic marker distinguishing ethnicities.
authors.affiliation: Department of Occupational and Environmental Hygiene, Chongqing Medical University, Chongqing 400016, P.R. China.
authors.forename: Yin-Yin
authors.initials: YY
authors.lastname: Xia
authors.affiliation: Department of Reproductive Biology, Chongqing Medical University, Chongqing 400016, P.R. China.
authors.forename: Yu-Bing
authors.initials: YB
authors.lastname: Ding
authors.affiliation: Department of Reproductive Biology, Chongqing Medical University, Chongqing 400016, P.R. China.
authors.forename: Xue-Qing
authors.initials: XQ
authors.lastname: Liu
authors.affiliation: Department of Reproductive Biology, Chongqing Medical University, Chongqing 400016, P.R. China.
authors.forename: Xue-Mei
authors.initials: XM
authors.lastname: Chen
authors.affiliation: Department of Occupational and Environmental Hygiene, Chongqing Medical University, Chongqing 400016, P.R. China.
authors.forename: Shu-Qun
authors.initials: SQ
authors.lastname: Cheng
authors.affiliation: Chongqing Key Laboratory of Birth Defects and Reproductive Health, Institute for Science and Technology Research of Chongqing Population and Family Planning, Chongqing 400016, P.R. China.
authors.forename: Lian-Bing
authors.initials: LB
authors.lastname: Li
authors.affiliation: Chongqing Key Laboratory of Birth Defects and Reproductive Health, Institute for Science and Technology Research of Chongqing Population and Family Planning, Chongqing 400016, P.R. China.
authors.forename: Ming-Fu
authors.initials: MF
authors.lastname: Ma
authors.affiliation: Department of Reproductive Biology, Chongqing Medical University, Chongqing 400016, P.R. China.
authors.forename: Jun-Lin
authors.initials: JL
authors.lastname: He
authors.affiliation: Department of Reproductive Biology, Chongqing Medical University, Chongqing 400016, P.R. China.
authors.forename: Ying-Xiong
authors.initials: YX
authors.lastname: Wang
mesh_terms: D000483:Alleles; D016022:Case-Control Studies; D002891:Chromosomes, Human, Pair 21; D019295:Computational Biology / Q000379:methods; D018899:CpG Islands; D019175:DNA Methylation; D030541:Databases, Genetic; D004314:Down Syndrome / Q000235:genetics*; D006801:Humans; D017422:Sequence Analysis, DNA