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 similar to 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.