Reduced apolipoprotein E-rich high-density lipoprotein level at birth is restored to the normal range in patients with familial hypercholesterolemia in the first year of life

Background: High-density lipoprotein (HDL) consists of apolipoprotein E (apoE)-rich and apoE-poor HDL particles. ApoE-rich HDL level is high at birth but decreases after birth with reciprocal elevation in low-density lipoprotein (LDL)-cholesterol. Objectives: The objective of the study was to clarify whether apoE-rich HDL decreases after birth in children with familial hypercholesterolemia (FH), a disorder caused by impaired LDL clearance. Methods: We measured apoE-rich HDL-cholesterol and LDL-cholesterol during the first year of life in 10 FH children (one homozygote and nine heterozygotes), 12 non-FH siblings, and 75 healthy controls. Results: At birth, apoE-rich HDL-cholesterol was undetectable in a homozygous FH child and lower in heterozygous FH children than non-FH siblings and controls (4 ± 2 vs. 12 ± 4 and 11 ± 4 mg/dl, P <0.001). At 3-4 months, apoE-rich HDL-cholesterol increased in homozygous and heterozygous FH children and decreased in non-FH siblings and controls. At 12 months, apoE-rich HDL-cholesterol levels were similar among these four groups (6-7 mg/dl). In contrast, LDL-cholesterol concentration was always twice as high in heterozygous FH children as non-FH siblings and controls (at birth, 50 ± 15 vs. 25 ± 7 and 25 ± 5 mg/dl, P < 0.001; at 3-4 months of age, 159 ± 29 vs. 71 ± 16 and 73 ± 15 mg/dl, P < 0.001; at 12 months of age, 156 ± 29 vs. 75 ± 18 and 76 ± 17 mg/dl, P < 0.001). Conclusion: ApoE-rich HDL level is low at birth in FH children and increases to the normal level in the first year of life, opposite to the change in normal children.