None of the patients were carriers of mutations in the LDL receptor (Trp23Stop, Trp66Gly, Trp556Ser, 313+1G --> A, 1846 - 1G --> A) or the apolipoprotein B gene (Arg3500Gln, Arg3500Trp, Arg3531Cys) associated with hypercholesterolemia.
The surprising result that only two mutations of apoB in the receptor-binding domain (Arg 3500 Gln and Arg 3531 Cys) were associated with defective LDL binding, hypercholesterolemia, or CAD is in stark contrast with familial hypercholesterolemia, where nearly 150 mutations of the LDL receptor have been described that disrupt its function.
These findings suggest that apo B R3531C is both less common in the UK and gives rise to a less severe form of hypercholesterolaemia than the classical 3500 mutation.