To this end, we 1) compared the DNA methylation profiles and mRNA expression profiles among uterine leiomyomas and myometrium with or without leiomyomas using an advanced genome-wide DNA methylation analysis method, 2) attempted to identify a subset of genes whose differential DNA methylation in the promoter is correlated with differential mRNA expression, 3) identified ER alpha-target genes that have aberrant DNA methylation in the promoter, and 4) examined the genotype of the X chromosome and the chromosome distribution of aberrant DNA methylation in uterine leiomyomas. The gene discussed is ESR1; the disease is leiomyoma.