CDKN2A and mucopolysaccharidosis: In addition, fluorescence-activated cell sorting (FACS) of the CD144+ cell populations from the femoral metaphysis followed by quantitative real-time polymerase chain reaction (qRT-PCR) analysis revealed that CD144+ cells from MPS-treated mice (vs. vehicle-treated mice) had reduced expression of cell proliferative marker Ki67 (Fig. 2j) and much higher expression of p16INK4a (Fig. 2k) and p53 (Fig. 2l), 2 cellular senescence-inducing genes.