Fluorescent labeling using Calcein green and Alizarin red staining in the incisor and femur of euploid and trisomic mice, respectively, at the age of 6 weeks (A). Mineralizing surface (B) was not significantly different in the femur or incisor between Ts65Dn and euploid mice. Mineral apposition rate (C) and bone formation rate (D) was significantly reduced in Ts65Dn mice in both the incisor and the femur. (Incisor; Eu, n= 13; Ts, n= 10; Femur; Eu, n= 11; Ts, n= 8)(**p ≤ 0.01, *** p ≤ 0.001)