Identification and Functional Analysis of APOB Variants in a Cohort of Hypercholesterolemic Patients

Figure 1. Flow diagram of the study process. The variants characterized are underlined.

Figure 2. Pedigrees of the families of the 2 index patients carrying the apoB p.(Lys3344Glu) variant. The index cases are indicated with an arrow; circle and square symbols represent women and men, respectively; and shadow-filled symbols indicate the members affected with FH. The first line below the symbols corresponds to the individual identification, the second indicates LDL-c levels before lipid-lowering therapy, the third indicates age, and the fourth indicates the amino acid change in apoB. (A) Pedigree of the family of patient 1. (B) Pedigree of the family of patient 2.

Figure 3. Competitive binding and uptake of LDL in HepG2 cells. (A) Ability of LDL from apoB p.(Lys3344Glu) heterozygous patient 1 and the control to compete with DiI-LDL for cellular binding (p < 0.001) and uptake (p = 0.014). (B) Ability of LDL from apoB p.(Lys3344Glu) heterozygous patient S1, apoB p.(Ser3801Thr) homozygous patient 3 and the control to compete with DiI-LDL for cellular binding (patient S1 vs. control, p = 0.014; patient 3 vs. control, p = 0.023; patient S1 vs. patient 3, p < 0.001) and uptake (patient S1 vs. control, p < 0.001; patient 3 vs. control, p = 0.503; patient S1 vs. patient 3, p < 0.001). Results are expressed as percentage of DiI-LDL binding or uptake in the absence of competitor LDL. The identification of each patient is indicated in brackets (see Table 1 and text). RFU, relative fluorescence units.

Figure 4. Competitive uptake of LDL by THP-1 macrophages. Ability of LDL from apoB p.(Lys3344Glu) heterozygous patient S1, the apoB p.(Ser3801Thr) homozygous patient 3 and the control to compete with DiI-LDL for cellular uptake (p = 0.420). Results are expressed as percentage of DiI-LDL uptake in the absence of competitor LDL. The identification of each patient is indicated in brackets (see Table 1 and text). RFU, relative fluorescence units.

Figure 5. Ability of LDL from apoB p.(Lys3344Glu) heterozygous patient S1 to support U937 cell proliferation. [Methyl-3H]thymidine incorporation into DNA was measured in disintegrations per minute (DPM). Data represent the mean ± SEM of four replicates and are representative of two independent experiments with similar results (p < 0.001). The identification of the p.(Lys3344Glu) carrier is indicated in brackets (see text).