These observations combined with what is known about the regulation of the isoprenoid biosynthesis pathway, have led to the following hypothesis for the pathogenesis underlying the episodic inflammatory symptoms in MKD (16, 20): under normal conditions, the increased HMGR activity in cells from MKD patients results in an elevated mevalonate level, which compensates for the decreased MK activity in the cells and assures a normal flux through the pathway. Here, HMGA1 is linked to mevalonic aciduria.