A familial hypercholesterolemia that is characterized by very high levels of low-density lipoprotein (LDL) cholesterol (usually above 400 mg/dl) and increased risk of premature atherosclerotic cardiovascular disease, and has_material_basis_in autosomal recessive homozygous mutation in the low density lipoprotein receptor adaptor protein 1 gene (LDLRAP1) on chromosome 1p36. [ url:https://ghr.nlm.nih.gov/condition/hypercholesterolemia http://purl.obolibrary.org/obo/ECO_0007636 http://purl.obolibrary.org/obo/ECO_0007637 url:https://www.omim.org/entry/603813 ]