APOB and familial hypercholesterolemia: Mipomersen is a 20 nucleotide-long antisense oligonucleotide targeting apolipoprotein B (ApoB) mRNA indicated in homozygous familial hypercholesterolemia (HoFH) exerting its action by binding to ApoB mRNA and inhibiting the subsequent synthesis of the protein through RNase H activation.