Twenty children with HeFH (aged 4.9-15.6 years) and 12 cardiac transplant recipients (aged 4.4-18.7 years and receiving triple immunosuppressive medication) who had participated in previous pharmacokinetic and pharmacodynamic studies with pravastatin were genotyped for the -11187G > A and 521T > C SNPs in the SLCO1B1 gene and for the 2677G > T/A and 3435C > T SNPs in the ABCB1 gene.