<qa>  What is the maximum amount of blood drawn for the first optional kinetics study?The LDL kinetic assessment will be performed using a primed constant infusion of deuterated leucine for 12 hours with repeated blood draws up to 48 hours. 2- 14 days following the start of the leucine infusion, subjects will be admitted to the research inpatient unit at University of Pennsylvania where the AAV8.TBG.hLDLR gene therapy vector will be administered. Vital signs will be monitored frequently for 24 hours. Blood will be drawn for safety testing daily for 3 days up to 72 hours and then weekly up to 12 weeks. More comprehensive assessment of safety parameters will occur every 4 weeks up to 12 weeks. Twelve weeks after vector administration, subjects that participated in the first optional kinetics study will be re-admitted to the inpatient unit at University of Pennsylvania or selected sites for a repeat LDL kinetics study. After this visit subjects will be permitted to resume LDL apheresis andor plasma exchange, and other lipid lowering treatments at the discretion of their caring physician. Subjects will have a safety visit with blood draw every 12 weeks up to 52 weeks, and will be followed with bi-annual telephone calls and annual lipid tests thereafter up to 260 weeks. 