OBJECTIVE: To study the correlation of genome-wide distribution of 6-methyladenine (6mA) of DNA in chorionic tissues from abortuses with monosomy 21. METHODS: Genomic DNA was extracted from chorionic samples from four abortuses with monosomy 21 and four without. After quality and purity test, partial DNA was subjected to chromatin immunoprecipitation with anti-6mA antibody, and then identified by sequencing. The sequencing data was analyzed by using bioinformatic software for the difference in 6mA between the two groups. RESULTS: Analysis of read peaks suggested that the control group have much more 6mA genes (n=4607) compared with the experiment group (n=1059). For chromosome 21, this difference is even more pronounced (8032 vs. 1769). Above results suggested that the level of 6mA modification in monosomy 21 is low. Gene ontology enrichment analysis and KEGG pathway enrichment analysis indicated that the absence of 6mA genes in monosomy 21 is closely related to the growth and development of embryo. CONCLUSION The 6mA modification of human genes may play a similar role to 5-methylcytosine (5mC) modification during the growth and development of embryos.