Qiang Zhang1, Xiaohong Guo2, Tian Tian2, Teng Wang3, Qiaoli Li4, Lei Wang4, Yun Liu4, Qinghe Xing5, Lin He6, Xinzhi Zhao7. 1. Children Hospital of Fudan University, Shanghai, China; Shanghai Key Laboratory of Prevention and Intervention of Birth Defects, Shanghai, China; Shanghai Center for Women and Children's Health, China. 2. Children Hospital of Fudan University, Shanghai, China; Shanghai Key Laboratory of Prevention and Intervention of Birth Defects, Shanghai, China. 3. Children Hospital of Fudan University, Shanghai, China; Shanghai Key Laboratory of Prevention and Intervention of Birth Defects, Shanghai, China; Institutes of Biomedical Sciences, Fudan University, Shanghai, China. 4. Institutes of Biomedical Sciences, Fudan University, Shanghai, China. 5. Children Hospital of Fudan University, Shanghai, China; Institutes of Biomedical Sciences, Fudan University, Shanghai, China. 6. Institutes of Biomedical Sciences, Fudan University, Shanghai, China; Bio-X Institutes, Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders (Ministry of Education), Shanghai Jiao Tong University, Shanghai, China. 7. Children Hospital of Fudan University, Shanghai, China; Shanghai Key Laboratory of Prevention and Intervention of Birth Defects, Shanghai, China. Electronic address: xzzhao@fudan.edu.cn.
Abstract
BACKGROUND: Early diagnosis of Turner syndrome (TS) may improve preventive measures and treatment. X-chromosome inactivation specific differentially methylated CpG sites (XIDMSs) that are high methylated in inactive X chromosomes (Xi) and unmethylated in active X chromosomes (Xa) may be potential makers for TS detection. METHODS: The candidate XIDMSs were screened from 9 male and 12 female DNA samples with normal karyotypes using the Illumina 450k array and validated by bisulfite sequencing PCR and pyrosequencing assay. X chromosome dosage was calculated according to the methylation level of multiple XIDMSs. RESULTS: Overall, 108 candidate XIDMSs were screened by the 450k array. Validations indicated that XIDMSs gathered and formed the X-chromosome inactivation specific differentially methylated regions (XIDMRs). Using 3 XIDMRs at SAT1, UXT and UTP14A loci, 36 TS, 22 normal female and 6 male samples were analyzed. Methylation levels of the 20 XIDMSs in the XIDMRs could distinguish between TS and normal female DNA samples, the X chromosome dosage was consistent with karyotyping data. Analyzing samples of 2 triple X syndrome and 3 Klinefelter syndrome patients suggested that this method could be used to detect X chromosome aneuploids other than TS. CONCLUSIONS: XIDMSs are widely spread along the X chromosome and might be effective markers for detection of TS and other X chromosome aneuploids.
BACKGROUND: Early diagnosis of Turner syndrome (TS) may improve preventive measures and treatment. X-chromosome inactivation specific differentially methylated CpG sites (XIDMSs) that are high methylated in inactive X chromosomes (Xi) and unmethylated in active X chromosomes (Xa) may be potential makers for TS detection. METHODS: The candidate XIDMSs were screened from 9 male and 12 female DNA samples with normal karyotypes using the Illumina 450k array and validated by bisulfite sequencing PCR and pyrosequencing assay. X chromosome dosage was calculated according to the methylation level of multiple XIDMSs. RESULTS: Overall, 108 candidate XIDMSs were screened by the 450k array. Validations indicated that XIDMSs gathered and formed the X-chromosome inactivation specific differentially methylated regions (XIDMRs). Using 3 XIDMRs at SAT1, UXT and UTP14A loci, 36 TS, 22 normal female and 6 male samples were analyzed. Methylation levels of the 20 XIDMSs in the XIDMRs could distinguish between TS and normal female DNA samples, the X chromosome dosage was consistent with karyotyping data. Analyzing samples of 2 triple X syndrome and 3 Klinefelter syndromepatients suggested that this method could be used to detect X chromosome aneuploids other than TS. CONCLUSIONS: XIDMSs are widely spread along the X chromosome and might be effective markers for detection of TS and other X chromosome aneuploids.