We also show for the first time that a heterozygous LDLR mutation combined with a homozygous LDLRAP1 mutation produces a more severe hypercholesterolemia phenotype in the same family than a homozygous LDLR mutation alone.
Autosomal recessive hypercholesterolemia (ARH) is an extremely rare inherited hypercholesterolemia, the cause of which is mutations in low-density lipoprotein (LDL) receptor adaptor protein 1 (LDLRAP1) gene.
No association was observed between common hypercholesterolemia and any polymorphisms or haplotypes of the ARH gene; however, we newly identified a rare Thr56Met missense mutation located in the phosphotyrosine-binding domain, which is the functional domain responsible for cholesterol metabolism.