Figure 4.

Different mutations reported in APOB, causing hypercholesterolemia (FDB) and hypocholesterolemia (FHBL). The APOB gene is constituted of 29 exons. The binding site for the LDL receptor originally described as site B is formed primarily by residues 3386–3396 (anciently known by 3359–3369). Regions 3475–3635 and 4363–4460 are the ones we classically sequence when looking for APOB mutations in ADH. Mutations causing familial hypocholesterolemia (FHBL) are distributed on the entire coding-region, and they are mostly nonsense, frameshift, or splicing variants. Few mutations causing hypercholesterolemia (FDB) are described in a particular region of APOB, the p.Arg3527Gln mutation being the most frequent one. Some others have been recently reported to cause ADH outside the classical regions of APOB, shown in italic; the p.Arg50Gln and p.Ala3396Thr are detailed in this article and highlighted in bold.