Liver Adiposity Effects on Pediatric Statin

Inclusion Criteria: * 8-21 years * LDL cholesterol \>130mg/dl (\>95% percentile) * SLCO1B1 c.521TT genotype * Provide informed permission-assent(\<18 yrs.) or consent (≥18 yrs.) * Fasting overnight (\~8 hrs.) * Enrolled in Cardiology Pharmacogenomic Repository Exclusion Criteria: * Pregnancy * Non-fasting * Non-removable metal in body or MRI unsafe * Currently on statin therapy and unwilling to wash out of statin therapy for at least 4 weeks prior to Visit 1 and throughout the duration of the study. * Underlying unrepaired congenital or acquired cardiovascular defects or repaired congenital or acquired cardiovascular defects with hemodynamically significant residual disease. * History of underlying or laboratory evidence of underlying intestinal, metabolic, autoimmune, renal disease that can alter rosuvastatin disposition\* (absorption, metabolism, distribution, or clearance) * Pharmacotherapy that interacts with statins (OATP1B1 inducers/inhibitors) \* * Inability to swallow a tablet * \>5x the age-specific upper limit of normal for AST, ALT, total and conjugated bilirubin * Diarrhea in the last 24 hours * Anything that would exclude a participant from completing an MRI, such as pacemakers, claustrophobia, or body habitus (e.g., weight greater than 350 lbs.)