LDLR and metabolic process: Autosomal recessive hypercholesterolemia (ARH) is an ultrarare genetic disorder of lipid metabolism caused by disruptive variants in both alleles of the gene coding for the low-density lipoprotein receptor (LDLR) adaptor protein-1 (LDLRAP1) (D’Erasmo et al., 2020; Bertolini et al., 2020; Tromp et al., 2022; D’Erasmo et al., 2018).