Several chromatin modifying enzymes such as HAT1, KAT5, HDAC6, MBD1, and DNMT3A were downregulated at gene expression level in women with post-menopausal osteoporosis and osteoarthritis, with superior quantity and quality of bone being directly associated with HAT1, HDAC6, and MBD1 expression [82]. The gene discussed is HAT1; the disease is osteoarthritis.