APOB and coronary artery disorder: In this regard, it is of interest that increased concentrations of small LDL particles (specifically LDL-IIIb and LDL-IVa and IVb) have been found to be selectively associated with a common single nucleotide polymorphism that increases hepatic apo B secretion and reduces LDL catabolism via upregulation of hepatic sortilin, and is linked to increased CHD risk [9], [10].