Single center, open-label, prospective investigation to quantify the effects hepatocellular fat has on hepatic statin transport and response in children and adolescents in obese and non-obese children and adolescents 8-21 years of age with normal, wild-type SLCO1B1 c.521TT genotype that are dosed rosuvastatin

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.)