METTL9 and osteoporosis: To elucidate the potential role of METTL9 in osteoporosis, we initially used data from the Gene Expression Omnibus (GEO) database to analyze METTL9 expression levels in osteoporosis patients, specifically, we obtained two gene expression datasets (GSE35956 and GSE35958) that contain data from primary osteoporosis patients and healthy controls.