Notably, the kinetics of CDK6 expression by MM cells showed a marked down-regulation upon 24 h exposure to exo-miR-433, and the subsequent increase to the initial level after a further 24 h of incubation (Figure 4F) suggested that the observed phenotype may be due to the reversible down-modulation of CDK6, which results in a reduced capacity to phosphorylate Rb, hindering progression through the cell cycle. The gene discussed is RB1; the disease is Miyoshi myopathy.