MMP12 and occult macular dystrophy: To determine the effect of OMD on the mRNA expression of MMPs and TIMPs in HTM cells, that of MMP1, MMP2, MMP3, MMP9, MMP11, MMP12, MMP14, MMP15, MMP16, MMP17, and MMP24, and TIMP1, TIMP2, TIMP3, and TIMP4 was quantified using quantitative real-time PCR (Figs 3 and 4).