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.